UPDATE 1-Sinopec Q3 net more than doubles, outlook uncertain

* Q3 net 16.6 bln yuan vs forecast for 16.5 bln yuan

* Says domestic demand for oil products has rebounded

* HK Shares down 1.3 pct before results, up 11.5 pct in Q3 (Adds detail)

By Sui-Lee Wee

HONG KONG, Oct 29 (Reuters) - Top Asian oil refiner Sinopec Corp (0386.HK) will struggle to repeat the surge in its quarterly profit as uncertainty about Beijing's fuel price reforms and higher crude prices weigh on its outlook.

Sinopec, which posted a more than two-fold rise in third-quarter net profit, benefitted from four fuel price increases in China this year, with the most recent in September.

Sinopec (600028.SS) (SNP.N), China's largest refiner, is well positioned to cash in on Beijing's fuel price reform launched this year, which grants refiners a guaranteed profit margin if crude stays below $80 per barrel. Rivals PetroChina (0857.HK) and CNOOC (0883.HK) have less refining exposure.

But with crude prices hovering near $80 per barrel and Beijing cutting fuel prices three times this year, analysts say the best might be over for Sinopec, which is among the world's top oil refiners by capacity.

However, China may soon raise retail fuel prices by 5-6 percent after benchmark crude prices rose more than 6 percent since Beijing's last price move, analysts said on Thursday. [ID:nPEK365823]

"Domestic demand for oil products has stopped falling and begun to rebound (and) demand for chemical products has bounced back," the company said in a statement.

Sinopec will see higher year-on-year refined oil product sales in the fourth quarter, despite posting a loss in its refining business in October, an executive said. [ID:nBJD003163].

HUGE TURNAROUND

Still, Sinopec's third-quarter earnings mark a huge turnaround for the state-owned refiner, which was forced to take losses at its refining operations for most of last year, squeezed between low state-capped fuel prices and soaring crude prices.

Sinopec's net profit totalled 16.55 billion yuan ($2.4 billion) for July-September, compared with a restated 7.4 billion yuan last year. Nine analysts surveyed by Reuters had expected a profit of 16.5 billion yuan.

Sinopec's results contrast with those of PetroChina (0857.HK), which reported a 23.5 percent fall in its quarterly profit. [ID:nHKF080493]

From January to September, Sinopec's crude throughput rose 2.99 percent, while its total domestic sales volume of refined products fell 5.53 percent.

Shares in Sinopec fell 1.3 percent to HK$6.63 on Thursday, compared with a 2.3 percent decline on the benchmark Hang Seng Index .HSI.

Sinopec rose 11.5 percent in July-September, outperforming PetroChina, which gained 1.9 percent. The Hang Seng Index rose 14 percent. (Editing by Don Durfee and Chris Lewis)