HONG KONG - China's top offshore oil producer CNOOC Ltd said a Canadian court had approved its acquisition of struggling oil sands company Opti Canada Inc.

CNOOCC said in a filing to the Hong Kong bourse on Sept 8 that it expected the transaction to become effective in the fourth quarter of 2011. 

CNOOC Ltd in July agreed to buy Opti Canada for $34 million and $2 billion in debt, bolstering its position in the Canadian oil sands.