Most union refinery workers stayed on the job without a contract today as their bargainers probed for a way to reach a wage settlement in accord with the Carter administration's wage guidelines.

A. F. Grospiron, president of the Oil, Chemical and Atomic Workers, let the union's contract with 100 oil companies expire at midnight without a strike after the union received a potential pattern-setting offer from Standard Oil of Indiana (Amoco).

The union's bargaining policy committee rejected other company offers today, clearing the way for a possible industrywide settlement based on the Amoco offer of an increase of 73 cents an hour the first year and an openended wage-renegotiation clause for the second year.

Amoco officials said the offer, which excludes newly hired and temporary employes from the wage increase, would leave Amoco in compliance with the administration's 7 percent guidelines, based on the company's average wage of $9.34 an hour.

It was unclear, however, whether other companies could follow Amoco's pattern and give a 73-cent hourly increase when their overall increase exceeds 7 percent because, in many instances, their average wages are lower.

The guidelines are not clear on this point, although they generally permit pattern, or "tandem," settlements based on a contract that conforms to the guidelines.

Grospiron asked the administration today for clarification of this question, indicating that a go-ahead sign for a pattern agreement based on the Amoco offer would be a "major encouragement" for a settlement without a strike.

Grospiron has called the guidelines unfair and has vowed to bargain without regard to them, even though he races the reality that the oil industry is pledged, so far at least, to abide by them.

He also realizes that the oil industry is so highly automated that it can operate for weeks, perhaps months, with only supervisory personnel. That reality blunts the effectiveness of a strike threat by the union's 60,000 oil workers.

Grospiron said he tried without success to get a clarification from the government in November on its interpretation of pattern settlements. He said he renewed the request today and officials indicated they would respond by Tuesday morning.

Sources said tonight one or more administration officials will fly here from Washington early Tuesday to inform the union of the government's position, underscoring the importance the administration apparently attaches to the decision.

Grospiron said advance sanction of the Amoco offer as a pattern for the industry would "simply show [the government] recognizes the problem and wants to avert a strike."

While most union members continued working today, about 3,000 OCAW members at Gulf Oil's Port Arthur, Tex., refinery went out on strike this morning. Officials at the union's headquarters here said the strike was unauthorized and was called over local rather than national issues.