Study on dynamic positioning risks of deepwater drilling device in shallow water area

The world’s advanced deepwater drilling and completion devices are divided into mooring and dynamic positioning. The industry recommended practice is mooring locating for water depth less than 1 500 m, while the adaptability and risk of dynamic positioning in shallow waters are little studied. This paper describes the principle and drift limitations of dynamic positioning, including the theoretical limitations and the measures to avoid risks. It also suggests on how to set the observation scope and proposes the factors, operational risks and countermeasures to be considered in using dynamic positioning for operations in shallow waters. In addition to the environmental factors and those that affect the emergence release time of deepwater drilling device, the extreme limits of riser system, strength of subsea well head and structural casing, communication system, and positioning sensor system also need to be considered. The countermeasures include well head device selection, riser system analysis, staff communication and training, user and contractor agreement, etc. The research results can provide some guidance on the use of locating method in shallow waters.