Shenzhen COSL Deepwater Technology Limited is the deepwater-focused subsidiary of China Oilfield Services Limited, the offshore services arm of state-owned CNOOC Group and a listed company on the Hong Kong and Shanghai exchanges. The COSL parent group operates a fleet of around nineteen seismic and engineering survey vessels, sixty-two drilling rigs and two hundred and forty offshore support vessels, supported by geophysical, logging, drilling fluid, directional drilling, cementing and workover service lines. Working from Shenzhen, the deepwater technology arm focuses on services that support floating production units, drilling rigs and other offshore tonnage in the South China Sea and at Chinese ports. Engineers and technicians carry out periodical servicing of lifeboats, rescue boats and inflatable liferafts on offshore installations, alongside hull ultrasonic thickness measurement, ultrasonic hatch cover tightness testing and watertight integrity verification on attendant vessels and barges. NDT and remote inspection programmes deliver condition monitoring of welds, structural members and pressure systems, while in-water inspection by qualified divers supports both class and internal asset-integrity reviews on jackets, monopiles and submerged hulls. The company benefits from the COSL track record in operations at water depths from fifteen feet to ten thousand feet, drilling depths to thirty-five thousand feet, and HTHP well operations, and from its international footprint across Southeast Asia, the Middle East and the Americas. The Shenzhen unit is recognised as a service supplier by ABS, Bureau Veritas, CCS and DNV, allowing its inspection reports to be used in class, flag-state and internal asset-integrity verifications on offshore installations and attendant vessels.