President Carter opened a second front yesterday seeking House Republican help to wrest a natural gas pricing agreement from a deadlocked House-Senate energy conference.

Told earlier in the week that the long-stalled gas bill was virtually dead. Carter called Democratic conferees to the White House Tuesday afternoon to offer his help in reaching a solution.

While these talk continued inconclusively yesterday morning with Energy Secretary James Schlesinger, Carter met with the eight House Republican energy conferees who have been completely shut out of the 4 1/2-month closed door negotiations on natural gas. Only once this year has the energy conference formally met in open session. All other meetings have been between a bipartisan Senate group and selected House democrats.

Implicit in Carter's meeting with Republicans, members said, was his realization that his original House Democratic allies in favor of continued gas price controls may prove unable to reach agreement with the Senate majority favoring deregulation and that he will have to look to House Republicans to get a bill through conference.

Rep. Jphn Anderson (R-Ill.), Senior House Republican energy conferee, said Carter telephoned him Monday afternoon to ask Republican help on the bill. Anderson replied that the Republicans would like to meet with him to discuss the situation.

Republicans complained to the president at yesterday's meeting that they have been "shut out of the process," Anderson said. He said the president responded that "he didn't think that was a very good way to write a bill." Anderson said the Republicans will meet with Schlesinger today and were invited back to talk to Carter again if they wish. Democratic conferees are to resume meeting with Schlesinger this morning.

Last year it was the House Democrats who went along with Carter's proposal to continue natural gas price controls at higher levels and extend controls to the intrastate market. The Senate voted with the industry to end controls after two years.

Carter promised his House supporters to stick with them. But as it became obvious that they wouldn't be a gas bill without some form of deregulation, the administration made clear it would accept what is could get out of the conference.

Carter has lost the support of young liberals who feel that the eight-year deregulation plan that a majority of House Democratic conferees has offered went too far. Now Carter is in danged of losing Rep. John Dingell (D-Mich.), principal author of the House gas bill. Dingell, who has claim to the title of Mr. Energy in the House, can also be a prickly character to deal with.

Dingell has been described as unyielding in conference on several crucial issues, including a method for imposing incremental pricing. That method would make large industrial users rather than homeowners bear higher gas prices up to a certain level.

One Democratic conferee quoted Carter as saying that if all the Democrats wouldn't go along with a gas compromise, "We'll have to do the best we can with other members." He interpreted this statement as aimed at Dingell and Rep. Bob Eckhardt (D-Tex.), who joined Dingell on the incremental pricing issue, and as meaning that House Republicans would be asked for help.

Rep. Thomas Ashley (D-Ohio), the House Democratic leadership's representative on the energy conference, said yesterday he expects that House Republican conferees will be included in negotiations in the future.

The administration's role in the gas talks was described by conferees not as trying to impose a settlement; but as offering its good offices - "to help us take the first step," said Rep. Philip Sharp (D-Ind.)

Schlesinger did propose compromise solutions on the most divisive issues. Ironically, his proposal on incremental pricing coincided with Dingell's and Eckhardt's on the point they consider most important.

Both House and Senate conferees' proposals would require the federal Energy Regulatory Commission to write an incremental pricing rule. Under the House plan, it would take effect without congressional review. The Senate insists on a one-house veto. Dingell fears that the Senate, which favors deregulation, would kill incremental pricing. Schlesinger proposed that there be no congressional review of this first rule.

Schlesinger proposed that price controls end April 30, 1985, instead of Dec. 31, 1984 as proposed by a majority of Senate conferees and mid-1985 as proposed by House Democratic conferees. He proposed that prices move up annually under the Senate formula and that the rule for reimposing controls for one two-year period be that proposed by the Senate.

Carter has based his hopes on reducing oil imports which now run at a level of $45 billion a year and bolstering the dollar abroad on his omnibus energy conservation bill which he sent to Congress a year ago next week. The entire bill has been held up waiting for a solution on natural gas.