Sheik Ahmed Z. Yamani, Saudi Arabia's minister of petroleum and mineral resources, will arrive at Harvard this morning under heavy security guard from Harvard and Cambridge police.

After meeting with President Bok at 11 a.m., Yamani will eat at the Faculty Club with several professors and will deliver a public address on the Organization of Petroleum Exporting Countries in Science Center B at 4:30 p.m.

Bok said last night has has "been informed that (Yamani's appointment with him) is a purely ceremonial visit" and that "the only information I have is that it's a courtesy call--of which I have two or three a week."

Officials of the Harvard police, the Cambridge police, the State Department's security division and the Saudi embassy declined yesterday to describe security arrangements for the visit. Saul L. Chafin, chief of University police, said yesterday the Harvard police "will have enough" security officers to protect Yamani while he is on campus.

James Sughrue, a Cambridge police captain, said last night the Cambridge police will guard the minister off-campus and that "as far as I know" Yamani planned to spend last night at the Memorial Drive home of A.J. Meyer, professor of Middle Eastern Studies and Yamani's escort for his Harvard visit.

The minister's speech here--open to Harvard students but officially addressed to members of Economics 2590. "Economics of Middle Eastern Oil," a ten-student seminar that Meyer teaches--concludes a ten-day visit to the U.S.

Yamani has requested that Harvard forbid outside reporters from covering his speech, which will be followed by a question and answer session. Meyer said yesterday.

Yamani opened his stay by attending a board meeting of the Arab-American Oil Company in San Francisco. The company is "for all practical purposes a Saudi Arabian company" and the meeting was Yamani's principal reason for visiting the U.S. a government source, who asked not to be identified, said yesterday.

After meeting in Washington, D.C. with Secretary of Energy James B. Edwards and Myer Rashish '45, Undersecretary of State for Economic Affairs. Yamani flew to New York several days ago, addressing the Foreign Policy Association (FPA) in a luncheon session yesterday at New York's Plaza Hotel.

The minister stressed the importance of U.S. Saudi relations but called the relationship "tinged with bitterness" because of the U.S.'s refusal to negotiate with the Palestinian Liberation Organization. Christopher A. Kojm, senior editor at FPA, said yesterday.

Yamani did not refer in his speech to President Reagan's recent decision to sell AWACS surveillance aircraft and of fensive weaponry to Saudi Arabia--an action Israeli officials have strongly criticized--but lauded the sales when some members of the audience of 1000 quizzed him alterwards, Kojm said.

Saudi Arabia needs the aircraft to defend its oilfields, which would be a "great prize" to the Soviet Union. Kojm said Yamani told the FPA members. Security for the visit was "pretty tight." Kojm said, adding, that Secret Servicemen and New York policeman guarded Yamani