Theoretical analysis of steel catenary riser laid on the sloped seabed

Abstract The steel catenary riser is a preferred solution in deepwater gas and oil exploration. Though the numerical solution can give a precise result, the theoretical analyses exhibit the advantages of more rapid calculation speed with a few parameters, thus making it more suitable for the preliminary design of the riser. Since the riser may be laid on the sloped seabed, the catenary theory was modified in this study to calculate the static behavior of the SCR, and the results were verified by the numerical model. The influences of the seabed inclination angle and heave motion exerted to the top of the riser on the TDP location were investigated. Since the riser rigidity was neglected in the catenary theory, the boundary layer solution was integrated into the model to accurately determine the mechanical behavior within the touchdown zone of the SCR. Based on the simulation result, it can be seen that both the TDP moving distance and riser maximum stress range are increased with the heave motion amplitude and the seabed slope, whereas the heave motion exerted to the hang-off point has a major influence.