U.S. Secretary of State Cyrus Vance discussed bilateral issues with top Mexican officials yesterday, but no progress was made in the two key areas: illegal Mexican migration to the U.S. and American purchase of Mexican natural gas.

The visit, Vance said on arrival Wednesday night, was part of the "consultative mechanism" established by the presidents of both countries one year ago to provide a permanent forum for reviewing bilateral affairs.

Clearly not designed to produce significant results, the intent of the visit is regarded as keeping relations with Mexico comfortable, an act of "good neighborliness" as one U.S. official said.

Vance was to meet later last night with Mexican President Jose Lopez Portillo.

Just as the permanent flow of illegal Mexican migrants is of major concern to U.S. policy makers, Mexico's inability to obtain a "reasonable" price for its natural gas in the United States has become a principal foreign policy issue here. The U.S. refusal so far to meet the Mexican price, pending congressional action, has provoked bitter statements from officials here and a wave of criticism in the local press.

Last week President Lopez Portillo said once again that Mexico no longer intends to export its huge gas reserves and is proceeding with construction of its nationwide gas distribution network to fulfill its own needs.

Yet officials on both sides have been eager to avoid a buildup of the tensions that existed under the previous administrations.

Foreign Minister Santiago Roel has traveled 11 times to the United States in the last year and it was evidently time for a visit by Vance, who had postponed his trip here several times.

Vance appeared to want to make up for this cancellations by repeatedly referring to his Mexican counterpart as "my good and dear friend" and "distinguished leader."

Personal ties between the Carter and Lopez Portillo administrations have been blossoming, and top Mexican officials were evidently basking in the attention they have been getting from Washington.Last January, Vice President Mondale came to Mexico on a courtesy visit while Rosalynn Carter and Carment Lopez Postillo have met several times.

All the same, in matters of trade Mexico feels strongly that its neighbor should lower its protectionist barriers against Mexican export products such as winter vegetables, steel, shoes and textiles. While the United States is the principal buyer of oil from Mexico's new wells, Mexico believes that its main trading partner should buy the agricultural products that the country needs to sell to prevent an intensification of the already serious poverty in the countryside.

Vance and Roel today signed treaties on maritime limits and broadened the existing extradition treaty.

Officials of both sides proudly pointed to another recent treaty that took the sting out of the growing irritation over some 600 American prisoners in Mexico. This treaty, which permits natives of both countries to serve their prison sentences at home, went into effect last December. Since then 290 American prisoners have returned to the United States where the majority have been released.

Another 17 American prisoners are expected to return May 15. There are still 294 Americans in Mexican jails at present, while frequent arrests, most of them on charges of marijuan smuggling, continue.