Mobil Corp. announced yesterday that Allen E. Murray will succeed Rawleigh Warner Jr. as chairman and chief executive officer when Warner retires Feb. 1 after 17 years as head of Mobil, the nation's second-largest energy company.

The expected promotion of Murray and two other top-level executives completes a succession that was signaled at least two years ago when Murray became president of Mobil Oil, the corporation's principal energy subsidary.

Richard F. Tucker was elected to succeed Murray as president and chief operating officer of Mobil Oil and vice chairman of the parent corporation. James Q. Riordan also was elected vice chairman, as well chief financial officer. Both appointments are effective Feb. 1, when Warner reaches retirement age.

Wall Street analysts predicted that Mobil, under Murray, will follow a different path than it has under Warner during the 1980s.

After two unsuccessful attempts at billion-dollar acquisitions of Conoco Inc. and Marathon Oil Co. in the early 1980s, Mobil last year purchased Superior Oil Co. for $5.7 billion.

But the debt added to Mobil's books, coupled with the unpromising outlook for the petroleum business, have dictated a new strategy for Mobil, several analysts said.

"Mobil under Murray has an imperative to try to reduce the levels of debt back down to what they were" before the Superior acquisition, said Sanford Margoshes, an analyst with Shearson Lehman.

Russell Miller, an analyst with Alex Brown, said he believes that Mobil will take some major steps to reduce debt by selling Montgomery Ward & Co. Inc., the struggling retailing company it has operated since 1976, or Container Corp. of America, another division. Earlier this year, Mobil announced a streamlining of Montgomery Ward intended to reshape it into "an independent, free-standing profitable company without Mobil ownership or financial guarantees," a step that some financial analysts saw as a prelude to its sale.

Mobil reported a $116 million loss for the third quarter, after setting aside more than half a billion dollars to cover the restructuring of Montgomery Ward.

Both analysts said they anticipate a possible change in Mobil's relationship with Saudi Arabia.

"We may see a tendency for a more pragmatic approach vis-a-vis Saudia Arabia, where Mobil may be less willing to enter into marginal or unprofitable deals," Margoshes said.

Under its former president, William P. Tavoulareas, Mobil concentrated on maintaining its long-term relationship with the Saudis, at times at the cost of buying oil at uncompetitive prices, Margoshes said. Now Mobil may look "more dispassionately" at the relationship, the analyst said.

Murray, who succeeded Tavoulareas as Mobil's president a year ago, joined Mobil in 1952 as an accountant and worked in financial, planning and supply positions before becoming president of the U.S. marketing and refining division in 1975.