As a massive international search for survivors continued in icy waters around the capsized oil platform in the middle of the North Sea today, it appeared that more than 100 men, most of them Norwegians, may have perished in the worst offshore oil drilling disaster in history.

By nightfall, Phillips Petroleum, operator of the rig, reported recovery of 38 bodies with an estimated 101 still missing. The French-made, Norwegian-owned oil rig was being used as a floating hotel in Phillips' Ekofisk oil field in the Norwegian sector of the North Sea.

Phillips spokesmen said 89 oilworkers who escaped safely from the platform when it collapsed and overturned last night had been rescued, some after spending the cold night in lifeboats on the rough sea.

Earlier today, Norwegian officials coordinating the rescue efforts of Norwegian, British and Dutch ships and aircraft announced that as many as 149 survivors had been found. But they later agreed that they were apparently in error.

"We're working as best we can from our own information," said one Phillips official by telephone from the American company's Norwegian headquarters in Stavanger, Norway. "The figures may change since all the lists disappeared with the platform."

Phillips estimated that 228 oil workers were in the four-story 336-bed living quarters on top of the 10,015-ton converted drilling rig when one of its five underwater pontoon legs broke off and the platform crashed into the water. No Americans are believed to have been among them, although there were as many as 30 British oil workers aboard and a few Finns and other non-Norwegians.

When the thick fog that had halted night air rescue operations cleared this morning, only the four large, brown pontoon feet of the upended rig could be seen above the water's surface. The living quarters remained about 90 feet below the surface. The fifth pontoon and its severed leg floated nearby.

As more than 45 ships of various sizes, 10 rescue helicopters and several other aircraft methodically searched for more survivors today, divers and a small submarine equipped with television cameras inspected the wreckage, seeking signs of life but finding none.

It was hoped last night that some men might have survived inside the submerged living quarters. Unable to reach that area for most of the day, the divers banged on the hollow steel pontoon feet and legs but heard nothing in reply, according to a Phillips spokesman, who said the divers would work into the night. The submarine reached the bottom of the wreckage and relayed back television pictures of all four floors of the living quarters from the outside, the spokesman said, but they showed no signs of life.

The living quarters, equipped with recreation rooms, kitchens and bunk rooms, housed men working on a number of nearby Ekofisk rigs, including Phillips' new Edda production platform just a few hundred yards away. The steel gangway that had connected the Edda platform with the felled Alexander Kielland was removed during a gale yesterday, leaving the large platform unharmed in the collapse. The Edda platform, which houses 85 oil workers in its own dormitory, was evacuated, however, until rescue efforts are ended and the wreckage is towed away.

The accident occurred during the storm at 6:30 p.m. yesterday, shortly after many of the men aboard the floating hotel rig had gathered in its movie room waiting for the evening's entertainment. One of the survivors, British oil worker Tony Sylvester, told reporters in Stavanger that he and about 85 other men were in the movie room "when there was this almighty crack.

"We rolled over to one side," he recalled, "and then this crack was followed by another one. This time she went over," listing at about a 45-degree angle and throwing people and objects wildly about. "There was chaos," Sylvester said. "Oxygen bottles and things were lying about everywhere and everybody was struggling to get out."

In the darkness, he and other survivors recounted, they clambered out of that and other rooms up the steep incline to the top of the tilting rig. "Everyone climbed to the top who could make it and just clung on," said Sylvester. "We were at 45 degrees for about 15 minutes and everyone thought that was it, then she went all the way over and everyone was in the sea."

He and others recalled being thrown into the water by the force of the crash. Most of those who survived apparently found rafts and lifeboats bobbing around them in the heaving waves. Even with the tent-like tops of the rafts pulled over them, however, the six men in Sylvester's dinghy were inundated and had to bail out with their shoes. Hours later, they were winched up to safety by the crew of a British Royal Air Force helicopter.

Norwegian oil worker Olav Forshein said he was able to find and put on warm outerwear and a life jacket on the sinking upper deck before jumping into the water and struggling near enough to the Edda platform to be pulled out by a rescue basket lowered from it. "It all took about 15 minutes," he recalled.

Many others apparently were not so fortunate and never reached the life preservers or rafts or even the outside of the platform. British Flight Lt. Jim Bellingall, returning from an unsuccessful search for survivors in 100-foot visibility early this morning, said, "In the water we could see dinghies big enough for 10 men. There must have been four or five dinghies but they were all empty. We could also see one-man dinghies but they were all empty. We could also see one-man lifebelts and rings -- the sort to have on boats -- buy they were empty as well."

Survivors and Phillips officials said the accident accurred too quickly for the workers to follow rehearsed lifesaving procedures. They repeat the drills every time they go out to a rig for a shift -- 14 days of half-on, half-off work.

Although some survivors and Norwegian newspapers speculated that the two sharp cracks were explosions or that the broken leg was the victim of improper refitting work, Phillips and Norwegian government officials said they knew nothing about what caused the accident. The high seas were not nearly so rough as the 4-year-old rig was purportedly built to withstand.

Norwegian officials acknowledged, however, that the Alexander Kielland was due to be moved back to Stavanger in just a few days to be converted back into a drilling platform. Its place was to be taken by its sister rig, the Henrik Ibsen, also owned by Stavanger Drilling. Today, the Norwegian government prohibited it from being towed out to sea until an inquiry determines the cause of the Alexander Kielland's tragedy.

At an emergency meeting this morning in Oslo, the Norwegian Cabinet ordered a special commission to begin the investigation next week. Prime Minister Odvar Nordli also toured Stavanger, where the survivors were taken to hospitals and hotels, and was briefed on the rescue effort.

For Norway, with a population of 4 million, it was a national disaster. Half-hourly news bulletins on radio and television were interspersed with funereal music.

Stavanger, Norway's confident, booming oil capital, "is not what it usually is today," said insurance executive and honorary British consul Colin Peck by telephone. "All flags are at half mast. The nation is mourning."

The impact was almost as great here in Britain, although no British oil workers were yet known to be among the dead. Energy Secretary David Howell said the accident was "a somber reminder and warning of the appalling conditions under which people work in the North Sea" on both sides of the agreed boundary dividing the British and Norwegian oil exploration sectors.

Although safety procedures are believed to be stricter in Norway than for offshore drilling anywhere else in the world, this is the second largescale accident to occur in the Norwegian sector in a decade of drilling.

In 1977, a blowout in an Ekofisk well spilled 150,000 barrels of oil into the North Sea, prompting a reexamination of safety and environmental protection rules. There have been numerous North Sea diving accidents and incidents of rigs losing their stability, with some deaths and many injuries.

Although oil drilling and production were temporarily halted today in the immediate area around the wreckage of the rig, Phime Minister Nordli said at Stavanger that Norway's offshore oil program would not otherwise be disrupted.