CNOOC Ltd. said on April 18 that CEO Yang Hua had resigned, less than a year after being appointed to the top spot, in the latest management shake-up at China's biggest offshore oil producer.

Yang will be replaced by Yuan Guangyu, who has stepped down as president due to his move. Yang will remain as chairman and non-executive director, CNOOC said.

Both executives are 35-year veterans of the company, having joined in 1982, according to the statement.

Xu Keqiang has been appointed executive director and president of the company to replace Yuan, CNOOC said.

The company did not give a reason for the changes, which come ten months after Yang was promoted to CEO and Yuan was named president.

The appointments come as the oil industry is on a surer footing than a year ago, with crude oil prices around $50 per barrel giving China's oil majors more confidence to ramp up spending for the first time in years as they seek to replace aging reserves and falling output.

In recent years, CNOOC has embarked on a big overseas expansion, with acquisitions including the $15 billion purchase of Nexen Energy. Yang was made chairman of Nexen in June last year.