Shortly after 2 p.m. Saturday, Libya's oil minister, Kamal Hassan Maghur, a pudgy man in an expensive-looking blue suit, stepped from an elevator in the Intercontinental Hotel into the lobby where he was mobbed by dozens of reporters, moving like an unruly wave toward the door. Snatches of questions were shouted:

"Output . . . quotas . . . prices . . . optimistic . . . meeting?"

The answer was unintelligible. But when played back on the tape recorders of the international media it turned out the Libyan's mind was on other matters. He had a toothache, he said, and was on his way to the dentist.

With bemused shrugs the pack dispersed to await the next oracle.

In the best of times, tracking the closed-door deliberations of the Organization of Petroleum Exporting Countries is a haphazard business, in which the lobby stakeout is an essential ploy. But OPEC's current London meetings--now 11 days old--have established a new standard for confusion.

After squeezing customers with ever higher prices for a decade, the 13 OPEC members now, because of the oil glut,must make Letter From London sacrifices. This involves a process of haggling that has proven prolonged.

Ahmed Zaki Yamani, Saudi Arabia's oil minister, has taken to furtively entering and leaving the hotel through a basement garage. When cornered by prowling reporters (many of whom have moved into the luxurious hotel), Yamani is invariably optimistic, predicting blandly that all will be well while thus far it has not been.

For mock cheerfulness, Yamani is rivaled by Indonesia's minister Subroto, who likens the talks to slicing up a cake. Iran's Mohammed Gharazi is the most outrageous, proclaiming on his arrival that he would "never" consider a price cut.

The most close-mouthed of the ministers is Mallam Yahaya Dikko of Nigeria. He sweeps through the lobby several times a day refusing to emit a sound despite the persistent pleas of reporters. Finally asked if his silence meant that he will say nothing under any circumstances, he replied: "Yes," uttering apparently his single public syllable to date.

BECAUSE THE LONDON meetings started out informally, they never got even the modicum of organization that OPEC sessions in their heyday have had. After 10 days, a spokesman for the organization, Hamed Zaheri, appeared for the first time but conceded that all he knew was what he had read in the newspapers.

Zaheri did, however, establish a press room, with coffee and cookies courtesy of OPEC. But since the only tidbits of information must usually be gathered by assaulting ministers in the lobby, the pressroom, cookies and all, is useless and empty.

The hotel management may well be the most frustrated. Handling hundreds of restless reporters and cameramen is tricky. So each day new regulations for crowd control have been promulgated. First journalists were banned from the lobby, but they infiltrated anyway.

Next, reporters who had rented rooms were told they had to stay in them rather than wait downstairs. Then, it was announced that everyone would have to leave at the weekend because of an insurance company convention. But for some reason, that approach was dropped too. There were unconfirmed reports that the insurance company fled the melee after taking one look.