The oil-services arm of China National Offshore Oil Corp (CNOOC) has launched a US$2.5 billion buyout of Norwegian offshore-oil firm Awilco, the Wall Street Journal reported. The acquisition, which is supported by Awilco’s board and two large shareholders, will be the fourth-largest international takeover ever for a Chinese company. The deal represents a 19% premium to the price at which Awilco shares closed Friday on the Oslo Stock Exchange. It also includes the assumption of a further US$1.3 billion in debt. For CNOOC, the move marks the first attempt to buy a Western oil firm since its failed bid for Unocal in 2005. Awilco owns the world’s eighth-largest fleet of oil rigs.