Dynamic behaviour of offshore floating production systems in deep water

After a short description of offshore systems proposed for oil and gas production in ultra deep water the first part of paper presents the physical aspects of their dynamic behaviour. The second part is devoted to the classical numerical tools used for dynamic analysis of floating vessels and for the risers analysis. As these tools have same drastic limitations, the main research activities are addressed to unsolved problems. Two of them are discussed in the paper the vortex induced vibrations of risers and the wave twit linearities and impacts on the vessels.