Research on Critical Depth of Water for a Deep Sea Semi-Submersible Drilling Platform Based On Dynamic Positioning

摘要

Dynamic Positioning System (DPS) is an essential requirement formarine vessels and in many offshore platform operations, in order tomaintain desired position and heading in the presence ofenvironmental disturbances from wind, waves, and current. Based onDPS, in operating condition, this paper makes time domain simulationof a semi-submersible platform’s motion induced by environmentloads in different directions and thrusters in three different kinds ofservice conditions (all thrusters available, arbitrary one thrusterunavailable and two thrusters on the same switchboard unavailable)by means of DPSEMI program, from which the critical depth of waterof this platform in operating condition when DP can meet the demandof precision for station-keeping is obtained. This paper also comparesthe critical depth of water in different ocean environment conditionsand different thruster service conditions, analyses the station-keepingability of DPS, brings up some new opinions about critical depth ofwater and points the way out for the research in the future.