VIENNA (AP) — Once the symbol of oil dominance, OPEC faces new challenges as its members gather for a ministerial meeting this week on how much crude to pump.

For the 12 oil ministers from countries ranging from Venezuela to Nigeria and Iran, the formal focus of Friday's get-together is to determine production levels. The consensus in the markets is that ministers will opt to maintain the status quo as prices for U.S. benchmark oil have traded in a narrow range a few dollars above $90 a barrel. Brent crude, the reference point for many international oil varieties, is just above the $100 mark some countries OPEC exporters consider the acceptable minimum.

With prices largely at acceptable levels, the ministers are expected to maintain the cartel's target at 30 million barrels a day. However, there may be an attempt to cut back on overproduction, now said to be running at nearly 500,000 barrels a day.

On his arrival in Vienna on Tuesday, Saudi Oil Minister Ali Naimi described the status quo as "the best environment for the market."

For analysts at Commerzbank in Frankfurt, that was a clear signal there would be little or no change in policy — the Saudis are the main driver of OPEC policy. As such, said a Commerzbank note, it is "unlikely that Friday's OPEC meeting will result in any change to production policy."

Beyond prices and output, though, the Organization of the Petroleum Exporting Countries faces other more complex issues, ranging from the ramp up in shale oil production in the U.S. and a potentially destabilizing spat between Saudi Arabia and Iran.

The rise in shale oil production in the U.S., the world's biggest economy, has an impact on OPEC as the country remains a main market for OPEC. Shale oil, which is extracted from rocks using heat, helped lift the U.S.'s total output up to a daily 7.4 million barrels per day this month.

The Paris-based International Energy Agency says total production could top 9 million barrels a day by 2018, which would mean near self-sufficiency for the U.S. as well as significantly less dependence on OPEC imports. It would also swell the U.S. influence on prices that OPEC polices have largely determined in the past.

Even so, OPEC will continue to be a major player on global crude supply as it still produces about a third of the world's oil. IEA chief Maria van der Hoeven said earlier this month that the organization "will remain an essential part of the oil mix for as long as we can tell."

Still, already frayed OPEC unity stands to further suffer as a result of fears of less dependency on its product.

OPEC powerhouse Saudi Arabia and its Gulf partners have the strength to adjust to cheaper oil prices. Naimi, the Saudi minister, recently said there was no need to fear new supplies because "there is enough (demand) to go around" for all oil exporters.

Others, such as Iran, Venezuela and some African producers, disagree, saying they need oil above $100 a barrel to do business.

Divisions also exist along political lines.

Iran is losing hundreds of thousands of barrels a day in oil sales due to international embargoes related to its nuclear program. Along with Venezuela, the country is angry that Saudi Arabia has sought to plug the gap left by overproducing.

Ahead of Friday's meeting, Venezuelan oil minister Rafael Ramirez told reporters that some OPEC countries were producing above their quotas for "geopolitical reasons" — an apparent allusion to the Saudis, Kuwait and the United Arab Emirates.

Saudi-Iranian rivalries also continue to stymie OPEC attempts to appoint a new secretary-general, who is the organization's voice between ministerial meetings.

Iran has put forward Gholam-Hossein Nozari, a former oil minister, while Saudi Arabia is nominating OPEC veteran Majid El-Munif as its candidate.

Present Secretary General Abdullah Al-Badry of Libya has already been extended several times because of the deadlock, perhaps the most visible sign of cracks in the organization's facade of unity.

With no sign that either nation was withdrawing its candidate, attention was focusing on Iraqi contender Thamir Ghadhban as a possible compromise. But any decision was likely to be deferred to a future meeting.