 HONG KONG, March 15, 2021 PRNewswire -- CNOOC Limited the Company, SEHK: 00883, NYSE: CEO, TSX: CNU today announced that Caofeidian 6-4 oilfield has commenced production. Caofeidian 6-4 oilfield is located in the Midwest of Bohai, with average water depth of about 20 meters. 