After fixing world oil prices at their highest level in history, the seemingly omnipotent ministers of the Organization of Petroleum Exporting Countries Flew home from geneva this week, leaving behind a legacy of uncertainty over the future of oil prices and the cartel itself.

The three days of offical meetings here ended in a swirl of contradiction and irony, including suggestions by some petroleum ministers that the world actually might be headed toward another temporary oil glut.

As if to underscore the murky outlook for the cartel and the international oil market, Saudi Arabia's Sheik Zaki Yamani told reported after the final communique was distributed, "I am sure right now you are already confused."

It was confusing indeed.

Instead of achieving the unified price the 13 ministers spoke so urgently about before the meeting got under way, the cartel ended up with a scrambled two to three-tier system, with prices ranging from $18 to $23.50

Instead of a firm pledge to end the wild gyrations in the spot market, where single oil cargoes are sold on a one-time basis at nearly twice Opec's "offical" price, the 13 spoke loosely of a gentlemen's agreement" about which no one seemed confident.

Even the new $23.50 a barrel ceiling -- the first ever set by Opec -- appeared to be under indirect fire at the end of the meetings as four ministers publicly called for a September price-fixing session, before the December meeting announced in OPEC's final communique.

As the meeting ended, there was a strident outpouring of reaction against OPEC.

From the Tokyo summit, President Cater went out of his way to denounce the cartel's massive price increase. And, for the first time in years, there was volley of criticism from Third World oil-importing countries. Despite OPEC's aid programs and evocative Third World rhetoric, the massive price increases this year have opened a fissure within the ranks of developing countries.

Under OPEC's new aid pledge providing an additional $800 million for the Third World, the cartel will give back only one dollar for each additional 10 they take from their Third World customers.

Drawing on the French view that the international oil market has always been controlled by cartels the Paris newspaper Le Monde knocked OPEC for not behaving as a cartel should. The argument simply is that a proper cartel should provide a stable and assured price of oil, and while it admittedly overprices its products, it should do so in an orderly fashion.

For OPEC, it is difficult to predict the next move.

A number of key ministers here, including the United Arab Emirates' Mana Saeed Otaiba, Iraq's Tayeh Karim and Venezuela's Humberto Calderon-Berti called for talks between "OPEC and the industrial countries on energy, aid and development.Those talks, however, already appear doomed.

"Neither side can negoitate when the market is in such wild transition," said one Western diplomat here, adding, "OPEC is so split -- who, after all, can we talk to?"

Still another ironic factor that came up repeatedly in private meetings here is the possibility that the world could be moving toward another temporary oil glut.

Both Yamani and Algeria's Nordine Ait-Laoussine warned in private sessions that with oil at $20 or more a barrel, and demand sagging due to the coming recession and conservation efforts, the market could be thrown into a temporary glut of 2 to 3 million barrels a day by the end of 1980.

Given OPEC's inability to agree on a unified pricing policy during a "sellers" market, some analysts here question the cartel's ability to prorate production if the market shifts to favor buyers.

OPEC's disarray today, compared with its relatively placid role a year ago, stems from three related factors:

While there is enough oil production capacity and proven oil reserves to last until the 1990s, OPEC countries -- which control the sources of oil supply -- have placed a ceiling on how much will be exported, leaving the world a thin margin of supply to meet new demand.

Meanwhile, OPEC changed its production and pricing strategies.

Up until the Iranian revolt, according to International Energy Agency analyst James Reddington, the cartel regulated its production to maintain a set price level -- generally targeted by the Saudis.

With the growing recognition earlier this year that Iran would not be a stable supplier of the 3.5 to 4 million barrels a day pledged by Ayatollah Khomeini's government, OPEC's strategy has shifted. Now, OPEC is geared to produce at a set level of about 30 million barrels a day or less, leaving the price to fluctuate widely depending upon market demands.

"Production has become more fixed than prices," Reddington said.

Intra-OPEC politics have changed dramatically.

While the shah was in power, Iran was OPEC's second leading exporter, sending as much as 5 million barrels a day into the world market. With Saudi Arabia, Iran was in a position to manipulate OPEC's prices and production policy.

While never stated publicly, the Nixon and Ford administrations, at Henry Kissinger's urging, never adopted an anti-OPEC posture because Riyadh and Tehran were regarded as pro-Western forces for stability in the Middle East.

In exchange for paying higher oil prices, Kissinger argued that the United States and its allies would receive an ensured and politically stable source of supply. Also, America's major oil companies and other corporations would be in a position to garner billions of dollars and a competitive advantage in trade with the OPEC countries.

Kissinger's policy which was quietly adopted by the Carter administration, unraveled earlier this year when the shah was forced into exile.

The whip hand for setting OPEC prices and production policies is no longer in Iranian hands. The result of the shah's fall, however, is that OPEC'S power is now more diffused and scattered.

If the West is to find major new sources of OPEC oil supplies, they will come from Iraq, not Iran. Iraq has moved its production upward nearly 1 million barrels a day over last year, and with 100 billion barrels of reserves, according to intelligence sources, Iraq is the best prospect for new OPEC supplies after Saudi Arabia.

Iraq's emergence as a major power within OPEC, however, is an element that the Carter administration and most other industrialized countries are not prepared to deal with today.

The most fundamental change in world oil markets over the last year, however, has been in the role of the Saudis.

While Secretary of State Cyrus Vance, Zbigniew Brzezinski and others administration officials have sought to minimize the links betweens the Camp David peace accords and Saudi oil policy, Saudi Foreign Minister Prince Saud has repeatedly told reporters and diplomats that the Saudis are linking their oil policy to the terms of a middle East settlement.

Reinforcing this before the Geneva meeting, Yamani said, the West cannot expect the Saudis to raise oil productions "while we have Palestinians living in tents,"

The Saudi signals are being delivered now by cautious technocrats such as Finance Minister Mohammed Aba Khay, who recently said that if the United States could move to resolve the Palestinian and Jerusalem questions, "all other problems would disappear," adding: "Obviously, we would give you more oil." CAPTION: Picture, Journalists crowd around OPEC ministers in Geneva's International Hotel before the oil cartel began talks on new price levels Tuesday. Ap! Graph, Daily Oil Production Levels of OPEC Countries, By Dave Cook -- The Washington Post