Under pressure from skeptical government oil experts, the Central Intelligence Agency is again revising estimates - this time upward - of the oil producing capabilities of Saudia Arabia, world's largest oil exporter.

Last month the agency dropped its estimates from 10.5 million barrels a day to 8.8 million. A separate classified report in December attributed the drop to political and economic decisions by the Saudia as well as mismanagement of the fields by the Arabian American Oil Co. (Aramco).

Energy Secretary James R. Schlesinger and other senior energy officials have been citing the reduced estimates by CIA's Office of Economic Research to stress the urgency of congressional action on the president's stalled energy program.

Projections of available Saudi oil production are regarded as signifficant because the kingdom, with a quarter of the world's petroleum reserves, is the biggest potential source of additional oil.

Schlesinger, who headed the CIA during the Nixon administration, visited Saudi Arabia in January and met King Khalid, Crown prince Fahd, Saudi oil minister Zaki Yamani and other senior Saudi officials. On his return to Washington, he told reporters that oil analysts in the past have tended to overestimate the Saudi's ability and willingness to produce oil.

One senior Carter administration official familiar with the CIA's analysis defended it earlier this month as "an honest piece of work . . . based on new intelligence."

The "new intelligence," however, has not gone down well among international oil analysts in the State and Treasury departments as well as in the major oil companies, especially the four Aramco parent companies: Exxon, Texaco, Standard Oil Co. of California and Mobil.

One government expert familiar with the CIA's approach said he considered it "frightening" that the agency could be so incorrent in dealing with what is essentially an engineering problem.

Another labeled the CIA study as "inept," adding that the agency could have made mistakes because of inadequate and outdated information.

A third analyst said the CIA study has "even less backing than the Soviet study," an agency report President Carter released last April when he sent his energy bill to the Congress. The CIA Soviet report has since been disavowed by a number of Carter administration officials, including Schlesinger who in private says he questions its conclusions.

Oil industry executives such as Aramco Vice President James V. Knight not surprisingly are critical of the accounts of the CIA report circulating in industry. Knight says Armaco can produce more than 10 million barrels a day now and , if called upon by the Saudis, they could nearly double production during the 1980s.

This week in response to what one CIA official described a "growing confusion" over the Saudi numbers, the agency changed the Saude entries in its unclassified "International Energy Biweekly Statistical Review." Last spring Saudi available production was pegged at 11.5 million barrels daily, then reduced to 10.5 The Jan. 11 issue, however, dropped the Saudis to 8.8, along with a carefully worded footnote citing the Saudi's articial ceiling on porduction.

While the interagency squabble over the classified Saude report raged the quietly CIA restored the Saudi available production to 10.5 million barrels a day lastweek in its Feb. 8 edition of International Energy review.