Iraqi officials cheered and clapped as the first oil field up for bid went to a major international consortium at the opening of the country's biggest postwar auction Friday. But from there, the chill set in.

Oil executives from around the world made deals on only two fields, both in Iraq's relatively stable south, while shunning six others in regions with sporadic violence _ and where the risk outweighs the profits that the Iraqi government is offering.

Iraqi officials portrayed the day as a success because they secured deals that will ramp up production in the two giant fields. But the lack of energetic bidding highlighted Iraq's difficulties in turning its wealth of oil _ the world's third largest reserves _ into a financial bonanza.

Energy experts say Iraq has been tightfisted in the deals it has offered major producers. There is also a long-running feud between the central government in Baghdad and the Kurds over control of petroleum reserves in the north.

Security is yet another issue, particularly in central Iraq and areas north of the capital. Violence in general has been down for more than a year, but dramatic attacks still happen. Bombings killed at least 127 people in Baghdad on Tuesday.

"Iraq can absolutely get big commitments" from oil firms, Samuel Ciszuk, Mideast energy expert with London-based IHS Global Insight, told The Associated Press. "But with the current situation, they can only make progress on the biggest and cheapest fields" where the security risks and development costs are low.

At fields in eastern and central Iraq, "risks _ both above ground and below _ are much greater ... and infrastructure is much less well developed," he wrote in a report on the day's auction. "The volumes produced from these fields are also far lower than from the south."

Oil majors in the U.S. have not spoken openly about the bidding process, saying only that there is interest in Iraq. On Friday, officials with Marathon Oil Corp., Exxon Mobil Corp. and Chevron Corp. had no comment.

"Given that Iraq's oil and gas reserves are among the largest in the world, they are going to play a key role in meeting the world's forecasted demand," Kirsten Smart, spokeswoman for the European oil giant Shell, said in London.

"We are committed to supporting Iraq to achieve a substantial production increase, using the most advanced technology that we can bring to bear," she said.

One big reason oil majors haven't rushed back into Iraq are the terms that the government is offering.

Companies must accept 20-year service contracts and receive a flat fee per barrel produced for their services instead of production-sharing contracts, which are much more lucrative.