When President Carter announced he would gradually end federal control of U.S. oil prices, some naive people assumed that government workers hired to set and enforce controls would be out of jobs.

However, the word is out at the Department of Energy, as more seasoned government-watchers anticipated, that virtually no bureaucratic mass will be lost.

Experts in and out of DOE attribute this not only to the agency's natural capacity to generate complex regulations that keep its employes occupied, but also to rampant confusion about what the president meant, exactly, and to feelings of doubt that decontrol will actually happen at all any time soon.

In any case, DOE is approaching "what in the bureaucracy is called a 'reallocation of resources,'" a department spokesman said.

Or, as a more critical observer on the House energy and power subcommittee put it, "These people survive. They are left over from the old Cost of Living Council under Nixon. There is plenty to be done, but up to not I don't think they've done a whole hell of a lot."

"Assuming the president meant to say what he said-and that's a big assumption-the controls will still be operating until a least 1981, and then they [DOE] have a lot of other stuff they claim they ought to be doing," said Washington public interest energy lawyer Martin Lobel.

The president's windfall profix tax plan alone should generate enough income for lawyers to provide "annuities for their grandchildren," Lobel said.

The agency has lived with a degree of planned, but never immediate, obsolescence through several incarnations. Some employes started in 1971 of Nixon's price commission, which became the Cost of Living Council, which was absorbed by the Federal Energy Office, which was absorbed by the Federal Energy Administration, which was absorbed by the current Department of Energy, officials said.

"In terms of the shock [of price decontrol], there is a tremendous sense of deja vu and considerable doubt that it will actually happen," said Edwin Mampe, director of petroleum price regulationsat DOE.

"Every budget I've been associated with at DOE, we have been preparing for dencontrol which didn't happen and, as a result, we come up chronically understaffed."

He held up a listof "regulatory priorities" for his office and said, "Of 44 items here, 14 would not be affected at all by decontrol . . . But I'll have to do a lot of work defending these needs to the budget-makers."

Everard A. Marseglia Jr., assistant general counsel for interpretations and rulings at DOE, said he expects "no impact" on his office, "even though the bulk of our work has to do with mandatory oil regulations.

"In the past, as certain products have been decontrolled, such as residual fuel and heating oil, people still continued to have questions about how the controls worked before they were decontrolled," he said. "We have requests pending that we intend to deal with."

When and if they no longer have to control prices, DOE administrators explain, they will have more time to "monitor prices, competition, trends, market shares and other things going on in the oil industry."

They will improve their collecting and analyzing of data, "which has been given short shrift up to now." Meanwhile, they will be writing regulations implementing the new rules, and dealing with the kaleidoscope of "oil oil, new oil and 'new' new oil."

And someone inevitably has to worry about what one regulator called "revising, devising and re-revising stand-by controls, with the authority to bring controls back."

"I'm sure there are some people here who are worried," said Doris Dwton, deputy assistant administrator in the office of fuels regulation. "Others worried when we decontrolled aviation fuel prices. But nobody was put on the street at all."

Some DOE managers indicated a concern that the agency's most valuable will think the time has come for them to leave, even though they were not forced to. Indeed, some economists and others with technical expertise indicated privately they have had standing job offers from oil companies or other federal agencies, which they may now accept.

The greatest anxiety can be expected among auditors and investigators, in Washington and 40 field offices around the country, whose jobs have been the most directly related to oil companies' compliance with the federal price controls, several DOE sources said.

Independent of President Carter's recent announcement, the DOE budget calls for the enforcement staff to trim itself from 653 to 252 positions between now and September 1980.

However, Gordon Harvey, an auditor and enforcement administrator, said, "I don't see it as having tremendous impact. . . We're primarily auditors, with accounting skills, and those skills are in demand."

For employes such as Harvey who are in the federal career service (as opposed to political appointees), the agency will try to find other government jobs, he said. He expects the Federal Energy Regulatory Commission (FERC) to hire most of the staff, to work on natural gas instead of oil.

Officials also expect some early retirements and other "natural attrition."

Several DOE staff members took issue with critics who contend the enforcement operation has been ineffectual against the oil companies. They vowed to continue to press active cases of violations.

"We wouldn't want the oil industry to think we're disaffected, that the enforcement program might peter out through poor morale," a DOE attorney said. "A lot of our cases are just beginning."

Still, as Harvey pointed out, "All these people knew they were joining a temporary organization. . . There will always be change, and as the energy picture changes, it is up to us to adjust. Well, I'm adjusting."