Mexico will be producing more than 2.7 million barrels a day of crude oil next year, up from 2 million barrels now, Cesar, O. Baptista, a vice president of Pemex, the Mexican National Oil Company, has predicted.

This had been the official target for output at the end of 1982. But Baptista -- speaking to a meeting here this week of the American Petroleum Refiners Association -- said, "We will get there as soon as we can, which will be sometime next year. Then we will see."

Mexican President Juan Lopez Portillo last March mentioned the possibility of hitting the target in 1981, but Baptista's remarks left no doubt Pemex was confident it would happen.

The country's need for cash probably will cause the government to decide next year to continue increasing production beyond the 2.7-million-barrel level, some Carter Administration sources believe. Pemex experts are said to think the country's prolific new oil fields, primarily off-shore in the Gulf of Mexico, can yield up to 4 million barrels a day without endangering future production by depleting oil reservoirs too rapidly.

Baptista said that Pemex is finding a new offshore oil field "every five weeks."

In the Campeche area, the offshore wells are huge producers, with the average well yielding 42,000 barrels of oil a day and one 60,000 barrels, he declared. The average well in the United States produces less than 20 barrels a day.

Mexico currently exports about 870,000 barrels of crude oil a day, and this figure soon will rise to 1 million, he said. About 80 percent of it goes to the United States, along with 300 million cubic feet of natural gas daily. The amount of crude coming to the United States is expected to increase but not as fast as exports, since other nations -- such as Canada and Japan -- are trying to buy more Mexican oil.

Baptista, who is in charge of Pemex's refining and petrochemical operations, said the company is expanding capacity rapidly for both.

Currently, about 85,000 persons are working on oil and gas exploration, production, transportation and processing projects, Baptista said, adding that Pemex plans to keep construction employment at the level for the next decade. "And you can build a helluva lot in 10 years with 85,000 people," he declared.

Mexico already exports 7,000 tons a day of ammonia -- an ingredient in fertilizers and other products often made from natural gas -- the most in the world, he said. Within two years Baptista expects exports of ammonia to reach 30,000 tons a day.

However, Baptista was uncertain how much of his nation's increased petrochemical production will be exported, since that will depend upon how fast the Mexican economy can grow.

Pemex is planning to double the country's refinery capacity from its present 1.1-million-barrels-a-day size. But Mexican consumption of refined products is growing by leaps and bounds, Baptista said. Mexico already uses more gasoline than Italy, and its consumption will pass that of France within a year. Therefore, he predicted, any exports of refined products are likely to be small.

Baptista said the money from oil and gas exports will be used to expand Mexico's industry and increase its output of food. "Oil is a tool" for that purpose, he said.

The limit set by the government on oil production, he explained, will be determined by "the digestion of money."