Random wave and vessel motion effects on drilling riser dynamics

Abstract

A computer model for dynamically analyzing a marine drilling riser has been developed. The model predicts a time history of riser stresses, deflections, and lower ball joint angle. This approach is novel in that it includes both random wave and vessel motion models. The random wave model allows one to specify any wave spectrum, from which the model generates a synthetic wave by decomposing the spectrum. The vessel motion model ties directly to the wave model and requires specification of the characteristics of the vessel's station-keeping system (mooring or dynamic positioning) and the vessel's response amplitude operators in surge or sway. Results of dynamic analyses of drilling risers will be discussed for various water depths.