SHANGHAI, Aug. 25 -- CHINA Petroleum & Chemical Corp, Asia's biggest oil refiner, may say first-half profit rose at the fastest pace in four years because of rising demand for gasoline and chemicals and falling costs for crude oil.

Net income probably increased 64 percent to 35.1 billion yuan (US$4.6 billion) in the six months ended on June 30, according to the median estimate of nine analysts in a Bloomberg News survey. Sinopec, as China Petroleum is known, is due to report by Monday.

Sinopec supplies almost two-thirds of the fuel sold in China, where the government forecasts gasoline consumption will rise 24 percent by 2010. An 8.1-percent decline in crude prices enabled Sinopec and rival PetroChina Co end losses from making fuels and selling them at state-controlled prices.

"International crude prices were at a low level, and it greatly helped Sinopec's refining business," said Grace Liu, an analyst with Guotai Jun'an Securities Hong Kong Ltd.

Sinopec relies on imports for 70 percent of its crude oil, while the government controls retail pump prices to limit inflation.

First-quarter profit almost doubled to 19.4 billion yuan from a restated 9.55 billion yuan a year earlier because of the drop in crude costs, Sinopec said on April 15. A 64-percent gain in first-half profit would be the biggest since 2003.

Sinopec's Shanghai-traded stock is the best performing this year among the 59 members of the Bloomberg World Oil & Gas Index, gaining 67 percent by Thursday's close. The Hong Kong-traded stock is up 13 percent, trailing the 15 percent advance in the benchmark Hang Seng Index.