China’s top three oil firms, along with India’s ONGC and Brazil’s Petrobras, have bid on a 20% stake in an Angolan oil field held by US energy company Marathon Oil Corp, Reuters reported. The sale, which is two-thirds of Marathon’s 30% holding in Angola’s Block 32, could fetch almost US$2 billion. Chinese refiner Sinopec has teamed up with China’s largest offshore oil company CNOOC to bid, while China National Petroleum Corp has also made a separate bid, according to sources familiar with the deal. Bidding for the sale has now finished and has moved to the negotiation stage, which could end within a few days.