Rep. Al Ullman (D-Ore.) warned yesterday that if Congress is to complete action on President Carter's energy bill this year it is an "absolute necessity" that House-Senate coferees settle their differences next week.

This presumably was intended, among other things, as notice to Sen. Russell B. Long (D-La.), leader of Senate conferees who has been sitting at the conference table for nine days without tipping his hand to what he will accept, that he had better start bargaining or there won't be a bill this year.

And if there is no energy bill this year, it is unlikely that in the 1978 election year Congress would vote the oil taxes that would be needed to fund the tax incentives Long wants to give producers to bring on more energy. The major issues that the conferees have not yet seriously discussed are the crude oil tax and natural gas pricing, both of which are of intense interest to the oil and gas industry in Long's Louisiana.

But Long just sat there beside Ullman, chairman of the conference on tax parts of the energy package, and said nothing. It is, after all, President Carter who wants the crude oil tax mot of all.

Then Ullman adjourned the conference until Tuesday to give him and Long time to try to resolve House-Senate differences on the Social Security bill and to give conferees on nontax parts of the package time to work on the issue of continuing price controls or deregulating newly discovered natural gas.

Long has said the energy tax conference should put off a decision on the crude oil tax until the other conference has completed its work so that House members who are conferees on all parts of the bill can join the tax conference.

But Harley O. Staggers (D-W. Va.), who chairs the nontax conference, said it would take "at least a week" to decide the natural gas issue. He does not expect to start it until Friday, at the earliest.

After six weeks of work, Straggers' group has settled most of the less controversial but highly detailed portions of the energy conservation package by hard bargaining. Conferees of one chamber propose a compromise. The other side debates it, rejects it, modifies or accepts it and then the conferees go on the next issue.

Very little of that has happened during nine days of meetings of the energy tax conferees. Most of the time was taken up by staff explaining the differences between the two bills. There has been a great deal of general discussion of the need to provide tax incentives to get more production of energy (Long) versus the President's and House's contention that his bill provides plenty of incentives.

Whenever the tax conferees have reached a point that is controversial, they have put it aside to come back to later. Yesterday they had a long discussion of an issue they passed over as too controversial earlier - whether heat pumps and wood-burning heaters should be eligible for home insulation tax credits as voted by the Senate.