BEIJING, Sept. 28 (Xinhua) -- China Oilfield Service Ltd (COSL),a listing arm of the country's largest offshore oil producer, CNOOC, got off to a flying start on the Shanghai Stock Exchange with its shares soaring almost 196 percent from its initial public offering (IPO) price to close at 39.9 yuan.

Asia's largest oilfield services provider opened 159.64 percent higher at 35 yuan per share on Friday, 21.52 yuan higher than its IPO price.

COSL's higher-than-expected debut, largely driven by factors like its relatively lower market value and the high international oil price, shows the market is optimistic about its future performance, said Wang Jing, an analyst with the Shanghai-based Orient Securities.

The Hong Kong-listed firms issued 500 million shares in the yuan-dominated A share market and raised 6.74 billion yuan (897 million U.S. dollars) for its Shanghai debut.

After its debut, the proportion of COSL's stake controlled by CNOOC was reduced to 55 percent from the previous 62 percent.

COSL was listed on the Hong Kong Stock Exchange in November 2002, issuing 561 million shares and raising more than 1.04 billion Hong Kong dollars.

In the first half of 2007, COSL earned 1.1 billion yuan in net profits, up 63.4 percent over the same period last year. Its business volume rose 48.6 percent to 4.26 billion yuan.

COSL chiefly operates offshore oil and gas prospecting, exploration and production services.