Cnooc Ltd., China’s biggest offshore oil and gas explorer, posted a 56 percent decline in profit for the first half of this year. Net income dropped to 14.73 billion yuan ($2.3 billion), or 0.33 yuan a share, from 33.59 billion yuan, or 0.75 yuan, a year earlier, the Beijing-based explorer said in a statement to the Hong Kong stock exchange Wednesday. That exceeded the 13.9-billion yuan average of three analyst estimates compiled by Bloomberg. Cnooc, which depends purely on oil exploration and production for revenue, is most exposed to oil’s plunge this year and must rely on cost cuts and capital spending curbs to boost profit, said Laban Yu, a Hong Kong-based analyst at Jefferies Group LLC. The strategy paid off last year, when it posted a surprise 6.6 percent profit increase. Brent crude has averaged about $59 a barrel in the first half of the year, down 45 […]