The runaway oil well polluting the North Sea for more than a week was capped today.

With Paul (Red) Adair, the Houston wild-well fighter, in command on the rig, disaster experts finally shut off the torrent of oil just before noon.

They then began pumping mud down the shaft to push the oil back 10,000 feet into the hold deep beneath the seabed from which it had escaped. Five hours later the pressure gauge on Bravo, the Phillips Petroleum Co. rig, read zero. The blowout had been killed.

In seven and a half days, it had spewed out more than 147,000 barrels of oil into waters heavily populated by fish and their plant food, according to Phillips. An estimated 18 per cent of the oil has evaporated, but that leaves about 120,000 barrels - 5,000 million gallons - floating in the sea and posing an ecological hazard.

Many Norwegians, while relieved that the battle with the well has been won, remain concerned about how it could have happened. They will want to know why their government has not compelled the oil companies exploiting the energy resources off the Norwegian coast to maintain adequate disaster equipment. They also question the inadequacy of the specialized vessels to clean up the muck after a well has blown. Only 2 per cent of the spill has been cleaned up, so far.

The Norwegian government, lured by the stream of revenues from oil, had planned to open up new sections of the North Sea for offshore drilling and production, including exploratory drilling in the wild and freezing region north of the 62nd Parallel where no rig has so far been allowed. These plans are now very much in question.

It is possible that the Phillips blowout could topple Premier Odvar Nordli and his Labor government in September's election. He sent a personal telegram of congratulations and relief as soon as he got word of the successful capping.

Efforts here will now be devoted to the cleanup process, which the Norwegian government says is Phillips' responsibility. The slick varies in size from 200 to 300 square miles, depending on the0, Col. 1> from 200 to 300 square miles, depending on the winds. So far, they have been kind, buffeting the slick from east to west and back, holding its center about 150 miles from the nearest coast of Norway.

So far, marine biologists have not spotted any dead fish or birds, but Bravo's Well 14 will almost certainly leave some unpleasant moments behind, either in the form of dead mackerel fish eggs or tarry stains on some shore.

Today's successful capping made a prophet of Adair, head of the red Adair Oilwell Fire and Blowout Co. He arrived here only yesterday and confidently predicted the gusher would be stopped "in a couple of days or sooner." He intended, he said, to meet his Monday appointment in Houston.

In fact, according to Phillips officials, the trick that worked had been worked out before his arrival. It came out of three-way talks between Adair's men on the rig, Phillips technicians and engineers at the Rucker-Shaffer Co. in California, makers of anti-blowout equipment.

In effect, the Adair team used the same technique that had failed on Thursday but with one crucial modification: A new set of so-called "blind rams," steel disks shaped like half moons wrapped in heavy rubber gaskets, were inserted in a housing called a blowout preventer.

This preventer had been inadvertently bolted upside down to the well last week by a Phillips contractor. That reduced the gripping strength of the rams as they tried to control the flow of oil and they were repeatedly forced apart on Thursday.

To overcome this loss of strength, the pistons slamming the rams together over the hole were made to travel a longer distance today. It was like a punch delivered from behind instead of in front of the shoulder and it carried extra force.

Today, the rams were to be smashed together hard enough to squeeze the rubber gaskets tightly.

A few minutes after 11 this morning, Adair, his deputies and some Phillips men, working in a steady shower of warm oil and gas, ordered the rams closed. This time they held.

The experts watched for 25 minutes. The rams held and the well was almost capped. Then the specialists bolted on a device to shrink the oil flow from a 13 5/8ths-inch diameter to 6 inches, small enough to be turned off by a capping valve on top of the structure.

The valve was turned and the runaway was capped. Pipelines were then hooked up from a nearby service barge, the Choctaw, to Bravo's platform. Through them poured the mud that forced the oil back deep into the seabed.

Tonight Adair told reporters, "It was nasty and hotter 'n hell - but it wasn't no big thing.It was a medium job."

His chief deputy, Asgar (Boots) Hansen, chimed in, "I turned to Red when it was over and said, 'Let's go home, buddy.'"

"It was very confining there on the platform," said Hansen, who had been on and off the rig since Sunday. "It was a little more messy, oily and closed in than we usually get and we do 35 to 38 jobs a year. But of course the well could have gone up anytime. Anything could have touched it off."

Asked why he did these things, Adair replied:

"I gotta wife and expensive tastes."

The Nordli government has been trying all week to play down the disaster. It yielded to political pressure Friday and ordered all production shut down in the Ekofisk field in which Bravo lies. Tonight, as a signal that all is well, the government ordered all rigs except Bravo to resume production.