Chinese officials are claiming that Vietnam is not capable of launching a military counteroffensive against China at this time because its oil reserves are virtually depleted.

This is the Major point in a detailed Chinese account of the strategy behind its 16-day incursion into Vietnam which has been leaked to the Yugoslav newspaper Politika's Peking Correspondent. It appears to be part of China's campaign to convince the world that it has indeed succeeded in teaching Vietnam a lesson.

Politika devoted much of its front page to the report. Citing "well-informed Chinese officials," it says the Chinese timed their invasion to take full advantage of Vietnam's alleged oil shortage. Correspondent Dragosly Ranchic reported "the little-know fact" that China was the main source of oil for Vietnam during the war against the Americans and continued supplying over half of Vietnam's fuel needs by pipeline right up until the Vietnamese invasion of Cambodia, when the taps were turned off.

Vietnam is reported to have received smaller amounts of oil from Algeria, Libya and Syria -- and the smallest portion of all from the Soviet Union.

According to the Chinese officials cited by Ranchic, the shortage of oil was also the reason why Vietnam did not deploy many of its regular troops during the fighting, but relied instead on frontier guards and militia units.

Politika reported that oil and other raw materials accounted for 52 percent of Vietnam's imports last year.

"The Chinese sources explained that the Peking leadership was aware of this weak Vietnamese point and that it was a major factor in weighing up the positive and negative consequences of military intervention in Vietnam," Ranchic wrote.

The officials added that China launched its attack at the moment when it believed fresh oil supplies from either the Soviet Union or the Middle East would take at least a month to reach Vietnam. At the time of the attack, Soviet ports in the Far East -- to which oil could easily have been shipped by the trans-Siberian railway -- were still frozen.

Yugoslav journalists in Peking often file stories unavailable to Western correspondents because of privileged access to senior Communist Party sources. Relations betweeen Yugoslavia and China have improved dramatically in the last two years following a 20-year rift during which President Tito was denounced by Peking as the world's leading revisionist.

According to Ranchic, the Chineses troop withdrawal began on March 4 -- a day before it was officially announced. He quoted Peking officials as saying that the Chinese army has created a "clean zone," about 15 miles into Vietnam, destroying all military installations.

Ranchic quoted the officials as saying Chinese troops had put two Vietnameses divisions out of action entirely and a third partially during a frontal engagement outside the town of Lang Son in the final battle of the war. The officials said it was during this battle that the Vietnamese used up their last reserves of oil, decided to allow the Chinese to withdraw peacefully and suggested talks on frontier problems.