Axial and Lateral Coupled Response of a Deepsea Riser for Scientific Drilling

Axial and lateral coupled response of deepsea drilling risers in hang-off condition was investigated. Lateral oscillation of riser has a possibility of being excited by axial tension fluctuation. The lateral response can be described by Mathieu’s equation of parametric oscillation. Numerical analysis method was formulated and verified by comparisons with experimental results. Stability conditions were clarified using the numerical method. Stability of the 4,000m riser for Scientific Drilling was also investigated and guideline for design of ultra deepwater risers was proposed.