For Canadian oil outfits that bought US firms last year, the spree is over

Less than a year ago Canadian companies ran wild in the US oil patch.

Like the last of the big spenders, they were tossing around billions of borrowed dollars for going concerns and land prospects in the United States.

The companies say domestic energy policies were what drove them over the border. With rough political and economic weather at home, the US looked like easy pickings for creditworthy, though cash-short, Canadian oil companies.

But the spending spree is over. Dome Petroleum, the largest Canadian-owned oil company, is trying to sell off its US assets. And the Canadian petroleum industry as a whole is at a virtual standstill; some companies are actually bankrupt or could go down the drain.

High interest rates on borrowed money and the ''Reagan recession'' are to blame for the sudden demise of the Canadian stake in US oil concerns, the ones north of the border say.

Although it is estimated that about $5 billion went south from here in the years 1978-81, no accurate figures are now available to illustrate the full extent of the Canadian invasion of the American petroleum industry. Most local industry experts agree, though, that in Canadian terms the investment was substantial, a sum equal to about half of the Canadian oil and gas industry's 1980 expenditures on exploration and development.

By far the biggest splash occurred with Dome Petroleum Ltd., having offered and acquired 22 million common shares of Conoco Inc. for $2 billion on June 10, 1981.

In a later swap of the Conoco shares for Conoco's 52.9 percent stake in Hudson's Bay Oil & Gas Company (later augmented by the purchase of all minority interests in the Canadian subsidiary), Dome Petroleum had become Canada's largest oil and gas operator in terms of production and reserves - but also in indebtedness.

Canadian chartered banks had eagerly extended over $2 billion worth of loans to Dome Petroleum last year and as much again to many others of their Canadian clients shopping for American corporations.

At the time, American critics pointed out that the Canadian financial institutions - unlike their US counterparts - could advance the entire purchase price in the form of callable loans at floating interest rates. US firms, when making stock acquisitions, must use some of their own funds to meet ''margin requirements.''

The rationale of Canadian oil companies was that rising wellhead prices and reserves in the ground would appreciate faster than the cost of the money they borrowed, resulting in a profit in the end.

Oil prices - and consequently the value of assets that usually secured these funds - fell, however, while the cost of the huge borrowings soared out of sight.

The ensuing financial crunch had compelled Dome and Husky Oil Ltd., another Canadian concern with a US stake, to put on sale their US assets, so far without much success. A host of smaller Canadian oil companies have practically abandoned their US positions regardless of the costs.

Their situation is not any better now at home than it was a year ago despite two federal moves to ease the National Energy Policy (NEP) of 1980 and an Alberta incentive program unveiled last April.

Partly because of federal wellhead taxation, Canadian oil industry cash flows and net earnings for 1981 fell 30 percent on the average. Some of the Canadian subsidiaries of multinational oil companies fared better than that average.

It didn't help that the markets for both oil and natural gas softened further. Many companies had idle productive capacity in the fields which was costly to maintain.

Meanwhile, about 38 percent of the corporate cash flows in the petroleum industry are needed to service an enormous debt load. Bank lending has almost completely dried up. In fact, several of the banks are said to be in difficulties themselves because of their overextended positions.

The federal lifesaver package of this spring is said to be worth about $2 billion through 1986, with most of the benefits accruing this year and next. The package is similar to Alberta's $5.4 billion incentive program of lowered royalties and cash credits.

But many industry people see the government relief as coming too late and delivering too little in the way of meaningful help for operators.

Massive layoffs of professionals in particular have already occurred. Cost-cutting measures include voluntary and involuntary salary cuts, elimination of fringe benefits, longer work hours, and a total ban on staff hiring.