Offshore Oil Engineering Co., Ltd., commonly abbreviated as COOEC, is a publicly listed company controlled by China National Offshore Oil Corporation, headquartered in the Binhai New Area of Tianjin and traded on the Shanghai Stock Exchange under code 600583. The firm is recognised as the only large general contractor in China holding integrated capability across the design, procurement, construction, offshore installation, commissioning and maintenance of offshore oil and gas development projects. Capabilities are organized around eight pillars covering offshore engineering design, offshore engineering construction, offshore engineering installation, offshore oil and gas field maintenance, underwater engineering inspection and installation, high-end skid-mounted product manufacturing, offshore engineering quality inspection and offshore EPC project management. Marine inspection activities began in the 1980s and now extend across all Chinese sea areas, with services including underwater inspection of jackets, pipelines, risers, mooring chains and subsea structures, together with onshore and offshore non-destructive examination using ultrasonic, radiographic, magnetic particle and dye penetrant methods. Hatch cover ultrasonic tightness testing, watertight integrity testing and other tightness-and-barrier inspections are performed on dedicated support vessels and offshore accommodation units within the fleet. Major offshore engineering manufacturing bases totalling some 3.5 million square metres are operated at Tanggu in Tianjin, in Qingdao and in Zhuhai, supported by a large fleet of installation, transportation, pipelay and accommodation vessels. CCS class approval underpins quality inspection work, with reports widely accepted by CNOOC affiliates and other operators.