Mexico has raised the price of crude oil for export by $2 a barrel to $24.60, the government oil monopoly Pemex announced today.

Mexico exports 530,000 barrels of oil daily, selling about 440,000 barrels a day to the United States, its main customer.

Mexico is not a member of the Organization of Petroleum Exporting Countries but has in the past reviewed its oil export prices every three months, increasing them in proportion to OPEC price rises.

This is the first time Mexico has raised prices without waiting for OPEC to act first.

Mexico is one of several petroleum-exporting countries that recently have raised prices over OPEC's official price spread, now ranging from $18 to $23.50.

Pemex, which does not sell oil on the spot market and negotiates with its customers on a quarterly basis, backdated the price increase to Oct. 1.

Mexico's price was $14.10 a barrel in January, rising to $17.19 in March and $22.60 in July.

Pemex officials said the new price tag is expected to bring an additional $15.2 million monthly.

Although the United States is Mexico's main customer for oil, Pemex also exports crude to Spain, Israel and some Latin American countries. Other European and Asian customers are scheduled to begin receiving shipments for the first time next year.

In 1980, Mexico will also begin exporting 300,000 cubic feet of natural gas daily to the United States at $3.625 per thousand cubic feet.

Mexican oil production this year is expected to average about 1.8 million barrels a day. Output next year has been fixed at 2.2 million barrels a day.

Mexican President Jose Lopez Portill announced Sept. 1 that Mexico has 54 billion barrels of proven reserves of oil and natural gas equivalent. Estimates of potential reserves range up to 200 billion barrels.