How many times in the past few years has the scenario been the same? The OPEC cartel announces a meeting, vowing to limit production and maintain artificially high prices. Then the cartel meets, but all OPEC members refuse to cut their production ''quotas.'' In fact, they are cheating on each other. So prices start to slide.

Then, financial-market analysts feign surprise and warn that the drop in prices may be only temporary -- and not altogether beneficial. If oil prices drop too far, consumption will soar and, inevitably, the United States will become too dependent on a resurgent OPEC.

It's fairly boring. But once again, this Middle East Kabuki play has been making the headlines as the OPEC ministers and the financial seers ignore the one underlying reality: as long as there is a glut, nothing that OPEC does in its bursts of theatrical posturing in Vienna will keep prices high.

The cartel members earlier had agreed to keep production down to 16.6 million barrels a day. But they have been turning out between 18 and 19 million barrels a day. That's at least 2 million barrels a day in excess of what customers need. Result: big inventories.

''It would appear that buyers do not want oil at any price today,'' said oil consultant Philip K. Verleger Jr. of Charles River Associates as prices collapsed.

Experts had anticipated that OPEC's mid-December meeting would be devoted to a debate over pricing, with a Saudi faction trying to maintain prices at $18 a barrel for another year, and Iran -- in desperate need of money to run the war with Iraq -- pressing to go to $20 a barrel. Some predicted that Iran would get its way.

Few were expecting that the latest OPEC meeting would end in almost total disarray. Not only was Iran's pitch for a $20 price ignored, but the Saudi faction couldn't ensure believability in the restated $18 floor, because no member would promise to stick to the self-imposed production quotas.

The Saudi group learned a lesson after the second oil shock of 1979-80: indiscriminate price increases cannot be sustained. High prices simply encourage exploration in the non-OPEC world, more conservation and substitution of other energy sources.

The Saudi group's present interest in a moderate oil-price policy clashes with that of the Iranian faction -- nations with lesser reserves and large, poorer populations. But the Saudis, hardened against Iran since last year's Iranian-inspired Mecca riots, held the upper hand. The glut is all too obvious.

Despite the U.S. Department of Energy's contention that oil reserves are declining, OPEC's own statistics put its proven oil reserves in 1986 at 645 billion barrels, up from 466 billion barrels in 1982. But the DOE, using an Oil and Gas Journal figure, still estimates OPEC reserves at only 477.5 billion barrels.

The DOE thus may be underestimating global reserves by around 200 billion barrels, according to New York oil maven Harry Neustein. He argues that there is enough oil to last at least another 50 years, even if not a single additional barrel is discovered.

As the OPEC ministers headed home from Vienna with no agreement, prices quickly broke through $17, and headed downward. Early this week oil was between $15 and $16 a barrel, and moving toward $12 a barrel, according to some analysts. Others still believe that OPEC will get its act together. They predict that prices will bottom out in a few months, then turn up, averaging $16 for 1988.

Neustein, a confidant of former Saudi oil minister Zaki Yamani, is bearish on prices. ''Nothing has changed,'' he says. ''The Persian Gulf states are determined to hold on to their shares of the market, and they will do it with price. The market determines the price, not the cartel.'' He sees oil prices dropping to perhaps $5 a barrel after the Iran-Iraq war is settled and the oil glut turns into a flood.

For the immediate future, oil doesn't have to drop that far to help cut the U.S. trade deficit: every $1-per-barrel saving lowers the trade deficit close to $2 billion, assuming imports of around 5 million barrels a day. And there are other prospective benefits in terms of reduced inflationary pressures and less pressure on the Fed to raise interest rates in support of the dollar.

To be sure, a continued slide in oil prices would be a further blow to the economy of the Southwest. The banking industry -- which bet on high-priced oil -- and the rest of the economy in oil-producing states such as Louisiana, Oklahoma and Texas are already hurting badly.

The bottom line was articulated as far back as 1981 by oil economist Elihayu Kanovsky: ''Economic forces point towards downward pressure on oil prices, and . . . if the major oil-price increases have not killed the golden goose for the oil exporters, they have at least inflicted serious wounds. It will not be surprising if the importance of Middle East oil continues to diminish.''