"Domestic demand for oil products has stopped falling and has begun to rebound, and the demand for chemical products has bounced back," Sinopec Chairman Su Shulin said in a statement.

Net profit at Sinopec, Asia's largest refiner by capacity, jumped to 16.55 billion yuan ($2.4 billion) for the three months ended Sept. 30, from 7.39 billion yuan a year earlier, helped by China's introduction in January of a more market-oriented fuel-pricing system.

As well as bringing the domestic price of refined products more closely in line with global crude prices, the reforms guarantee China's refiners a 5% profit margin as long as the price of international crude is below $80 a barrel.

Sinopec processed 134.39 million metric tons of crude oil in the January-September period, up 3% from 130.49 million tons a year earlier.

In contrast, lower crude oil prices and weaker energy demand knocked the quarterly earnings of Cnooc, which is mainly a production company, and those of its rival, PetroChina.