The Iranian oil industry, vital not only to the West but to the survival of governments in Tehran, has recovered relatively well from the chaos of Iran's revolution.

As far as revenue is concerned, the state-owned National Iranian Oil Company never had it so good, not even when it was producing a third more crude during the rule of Shah Mohammad Reza Pahlavi.

But at the same time, Iran's oil industry has never been so vulnerable. Since the monarchy fell -- brought to its knees earlier this year largely by a crippling strike in the oil fields -- the industry again has become caught in a cross fire of contending political forces.

It is a situation that, if aggravated by further upheavals, could make the flow of Iranian oil even more undependable and, possibly, lead to another shutting off of the taps.

In the business of producing and selling oil, the National Iranian Oil Co. is unarguably serving national interests better than ever before.

At a time when most other sectors of the economy remain paralyzed by postrevolutionary chaos, oil industry operations are running reasonably smoothly. The oil company has largely overcome dismantling of the Western consortium that had managed operations and marketing for the previous 25 years.

However, the turmoil and mounting opposition to the new government of Ayatollah Ruhollah Khomeini have exposed oil installations to sabotage and cast doubt on the future reliability of company personnel from the boardroom to the oil fields.

Highlighting government concern about keeping the peace in oil-rich Khuzestan Province, Prime Minister Mehdi-Bazargan today led a top-level delegation to the area on the eve of naval maneuvers in the Persian Gulf. The official news agency said the delegation was discussing problems of oil distribution and production with local officials, but it did not elaborate.

Under the direction of Rear Adm. Ahmad Madani, the governor general of Khuzestan Province, the Arab political movement and the guerrilla groups charged with blowing up oil and gas pipelines serving Abadan refinery this summer have been suppressed by summary executions of alleged saboteurs and mass arrests of opposition activists.

Continuing arrests by the security forces suggest, however, that the risk of more attacks has not been eliminated.

Less drastic than sabotage but equally menacing for Iranian oil exports is the threat of agitation or strikes by leftist oil workers believed to have a significant following in the oil fields and to have played a major part in organizing the strikes against the shah.

It may not, however, take political upheavals to bring a drop in the level of Iran's oil exports.

Next month the National Iranian Oil Co. is due to start renegotiating the long-term sales contracts that account for all but a small percentage of Iranian exports.

So far, there is no evidence of any government intention to reduce the volume of oil exports, oil company management sources say. But members of the government present a different picture.

With foreign exchange reserves now pushing close to $12 billion and oil revenues far exceeding expenditure, one of the revolutionary government's biggest headaches is how to dispose of its income.

Boosted by the shortage of oil on international markets, the price of Iranian crude has jumped within less than a year from less that $15 a barrel to between $20.11 a barrel for lowgrade heavy oil and $22.21 a barrel for light crude.

With oil exports officially pegged at 3.3 million barrels a day, the financial yield is reckoned at $75 million a day or more than $25 billion a year, roughly 25 percent up from the revenue collected by the shah with oil exports of more than 5.3 million barrels a day.

A widely expected price rise at the next OPEC conference in December would increase the attractions of an export cutback.

There are, however, widespread doubts about the actual volume of Iranian oil production and exports. Faced with persistent reports of a serious drop -- some say as much as 1 million barrels a day -- a sensitive Iranian oil company management has clamped down on the flow of oil industry statistics here.

The management insists that there has been nothing more than the usual operating fluctuations, which apparently means drops of anything up to 400,000 barrels a day. These drops showed in oil figures, but were not recognized in official statements.

The oil company's credibility has not been helped either by a statement by Khuzestan Governor General Madani indicating -- despite oil company denials -- that a recent drop in exports was caused by friction between leftist and rightist workers at the Kharg Island loading terminal.

Inconsistencies have also cropped up in reckonings of Iranian oil export levels by Western oil companies and the U.S. Department of Energy. The United States evidently has not been affected by the recent reported shortfalls and is getting nearly as much crude from Iran now as before the revolution.

How long Iran will be able to sustain production at the claimed rate is a topic on which there is no hard, recent information and no consensus.

Fears that production may slump within the next few years, leaving Iran barely capable of producing 3 million barrels a day, have spread since the revolution amid reports that oil well maintenance is down, exploration and test drilling for new reserves has been slashed and gas reinjection programs that are essential for the maintenance of oil well pressures are at a standstill. In short, the opinion of many experts is that Iran lacks sufficient skills to keep the oil coming out of the ground.

The arguments do not, however, pass unchallenged. Other oil analysts estimate that the National Iranian Oil Co. has sufficient skilled manpower to handle routine maintenance of wells and equipment at the lower rate of production that now prevails.

Apparently more urgent is the oil company need to revenue gas reinjection programs, which, for several years up to the revolution, had been absorbing annual expenditure of more than $1 billion in an attempt to prolong the life of Iran's oil fields.

"We have to do it even with production of only 4 million barrels a day," said Jahangir Raoufi, the company's head of oil field operations. "We need to get some of these projects back now."

But further progress on the program depends on the return of foreign contractors.

For months, discussions reportedly have been in progress between foreign companies and NIOC Fields, successor to the Western consortium's subsidiary, the Oil Service Co. of Iran, but without visible progress.

The delay is partly the result of internal reorganization in the oil field operations to replace the roughly 600 foreign technicians and managers withdrawn during the revolution.

Another major holdup appears to be a complete review of gas resources and their allocation for different projects. As a result gas liquefaction facilities that are ready for commissioning stand idle, and work on others is virtually at a standstill.

A third consideration, observers believe, may be the reluctance of some sections of the work force in the south to see foreign staff return.

National Iranian Oil Co. management has limited number of foreigners to return -- the figure was originally set at about 100 and then reduced to around 30 -- and several foreign contractors are back in operation.

At the same time, purges at all levels of those considered tainted by their service under the past government have drained away critically needed skills and experience.

Since his appointment in February, National Iranian Oil Co. Chairman Hassan Nazih has made strong representations to workers on the need to keep experienced staff and the need for greater labor discipline.

His face-to-face negotiations with workers have earned him considerable popularity and reduced the lists of managers singled out by workers' committees for dismissal.

In the present turbulent politics of Iran, however, Nazih's future is far from assured.