President Carter's energy plan, which emerged nearly intact from the House Aug. 5, faces its most serious political test in the Senate.

The chief target of senatorial critics, including such influential figures as Senate Finance Committee Chairman Russell B. Loug (D-La.), is the provision which determines the distribution of some $30 billion in crude oil taxes expected to accumulate by 1985 under the House version.

Under the House-passed energy bill, the proceeds would be returned to taxpayers in the form of tax credits tha first year and newer withholding afterward. This was substantially what President Carter proposed.

Long and other senior members of the Finance Committee - reflecting in part the oil industry's views - the other ideas about how to parrel out the proceeds. long would like to channel some of the tax bonanza back to the companies as a production incentive.

Another producing-state senator, Lloyd M. Bentsen (D-Tex), said he will move to increase production from some wells by exempting them from the pricing regulations and the House proposed oil tax.

Energy Secretary James R. Schlesinger Jr. calls the crude oil tax the "centerpiece" of the Carter plan. The tax which would raise domestic oil, now averaging about $8 a barrel, to the $13.50 world oil price over the next three years, would add about 8 cents a gallon to gasoline and other oil product prices by 1961.

Administration officials expect that Long will maneuver to set aside up to 25 per cent of the oil taxes for added production incentives.

One oil executive said, "Sen. Long has told the companies we can get more incentives in there, but we can't call it a "plowback." An industry attempt to enact a tax "plowback" - the return of taxes to the companies - was defeated in the House.

Long and other Finance members said last month they are also considering such major changes to the House bill as:

Reducing from three years to two the tax phase-in period - a provision Schlesinger does not oppose.

Committing some tax revenues to develop alternative fuel sources such as oil shale, coal gasification and geopressurized gas.

Boosting the gas-guzzler tax on cars not meeting mileage efficiency standards.

The House bill's heating oil rebate, which speaker Thomas P. (Tip) O'Neill Jr. (D. Mass.) maneuvered to keep intact, may also be contested in the Senate.

Some Southern members of the Finance Committee are skeptical about this provision benefiting New England and other Northern states, and may try to kill it.

There will also be a major drive to stitch special interest provisos into the bill benefiting domestic refiners. Sen. Floyd K. Haskell (D-Colo.) is already pushing an amendment to levy tariffs on imported oil products to offset a price edge domestic refiners would lose under the House bill.

While the outcome of the crude oil tax fight is unclear, the lobbying battle is already under way.

The central contest, as in the House, is between the administratin and the oil industry.

Schlesger has argued that the major oil companies are "awash in cash flow . . . unable to place that cash in exploration." The administration also charges that boosting oil revneues won't lead to the major new discoveries the companies promise.

The American Petroleum Institute's Charles J. DiBona disagrees. He says the industry must double oil development investment to meet Carter's 1985 goals. "We advocate the gradual or phased removal of controls on crude oil over an approximately four-year period," DiBona says.

Some oil executives say ending oil price controls is unrealistic in the current political environment. Instead, they are calling for a combination of tax exemptions or credits, and wider definitions of oil not subject to price controls.

There are still other major lobbying campaigns to knock out the crude oil tax altogether. The heaviest players here include a diverse and very loose coalition of labor unions and industry groups such as the air Transport Association and the National Oil Jobbers Council.

The AFL-CIO is against it because of the impact it would have on consumers and jobs in some member unions. The Teamsters are fighting it because of price increases in diesel oil. "It's a question of job for our guys," one Teamster official said.

The Oil. Chemical and Atomic Workers Union has also launched a heavy lobby against the tax on behalf of its 70,000 members working in refineries.

While some Senate aides already predict a floor fight led by Sen. Edward M. Kennedy (D-Mass.) when Long bring his bill before the full Senate in October, everyone agrees the energy tax battle in the weeks ahead will be a test of Long's celebrated legislative virtuosity.

One old Senate hand was more confident. "He will move to center stage, work a few miracles, and get a bill through." The real question, he added, is "what the Carter energy play will look like then."