Senate Majority Leader Robert C. Byrd (D-W.Va) said yesterday he is "reasonably confident" the Senate will cut off a threatened filibuster against the natural gas pricing agreement, which will be taken up this week.

Byrd's prediction came as House-Senate energy conferees got their first look at the staff report on the complex gas compromise.

The report, more than 300 pages of legislative text and explanation, was circulated yesterday among the congrees, who will have three days to read and digest it and then, it is hoped, sign the papers so they can be led with the Senate.

Byrd said the Senate would take up the agreement Thursday or Friday and he would let a filibuster run two days before filing a cloture petition, which would be voted on two days later. Sixty votes are needed to limit Senate debate, and Byrd said it may take more than one try to obtain them.

Democrats James Abourezk (S.D.) and Howard Metzenbaum (Ohio), who led up the Senate last fall in a filibuster against a price deregulation bill, are again expected to lead the opposition against the conference report.

President Carter's original natural gas proposal was to continue controls on interstate gas, consumed in the state where produced, but to raise the ceiling as of 15 months ago from $1.45 to $1.75 per thousand cubic feet (mcf) and let it rise with inflation.

The House concurred, but the Senate voted for an end to controls in two years.

After eight months of haggling, the conferees agreed to end controls on new gas by 1985, though controls could be reimposed by the president of Congress for one 18-month period that could run through the end of 1988. The ceiling would be about $1.93 per mcf now and would rise by about 10 percent a year, assuming an inflation rate of 6 percent.

The conference report, written by House and Senate staff, said this would mean an increase in producers' revenue of not more than $9 billion by 1985. This would be an increase of 6 percent of what they could expect under present law.

The report also predicts that this resolution of a 24-year struggle over price controls on natural gas would mean more production. It estimates that by 1985 that increase will be the equivalent of 700,000 barrels of oil a day, about 10 percent of present imports.

An analysis of the gas compromise by the Energy Department says producers stand to gain $28.5 billion-over the next six years.

Some liberals, led by Abourezk and Metzenbaum, oppose the compromise as giving too much to producers, while some conservatives oppose it for dragging out deregulation too long.

In another energy area, Senate conferees have decided to give up a ban on the sale of gas-guzzling cars. Energy tax conferees had alternately approved a tax on sale of gas-guzzlers, non-tax conferees dropped the Senate ban on them. Rep. Harley O. Staggers (D-WVA), conference chairman, said he will convene the conferees this week to vote on dropping the ban.

That would complete conference action on all parts of Carter's energy package except the tax section, which is by far the most important.

The tax conferees have met only once this year, to give the appearance of being at work when Carter went to the economic summit meeting in Bonn. He wanted to persuade America's anxious trading partners that this nation is getting on top of the energy problem - its reliance on expensive oil imports.

The centerpiece of Carter's energy package was to be a tax on domestic crude oil, to reduce use by taxing prices up to world levels. The house passed it but the Senate rejected it, and most observers consider it dead, three months short of the congressional elections.

Carter may get soemthing called an energy tax bill, but it seems likely to be limited to: credits for taxpayers who insulate their homes; a modified tax on guzzlers, and perhaps part of his tax on industrial use of oil and gas to push industry to coal.