Parametric analysis on the global design of flexible riser under different environmental conditions using OrcaFlex

Area of Science:

• Marine Engineering
• Ocean Engineering
• Subsea Systems

Background:

• Flexible risers are crucial for marine fluid production.
• Deep-water applications present significant design complexities.
• Understanding riser behavior under pressure and environmental loads is vital.

Purpose of the Study:

• To investigate the design challenges of a flexible riser at 2000m water depth.
• To analyze the global performance of lazy-wave configurations for flexible risers.
• To assess the suitability of hybrid configurations and riser models for sustainable marine structures.

Main Methods:

• Extensive dynamic analysis and parametric variations were performed.
• A multi-layered flexible riser model was developed in OrcaFlex.
• The model was subjected to internal pressure and environmental loads, with validation against existing lazy-wave models.

Main Results:

• Global analysis identified key influences of effective tension, bending moment, and environmental conditions.
• Stress, tension, and bending moment profiles were analyzed for the riser.
• The study assessed riser performance connected to a vessel under three environmental conditions.

Conclusions:

• The lazy-wave configuration shows promise for flexible riser design in deep water.
• The adopted configuration is suitable for a sustainable marine structure.
• Future research should include fatigue analysis for comprehensive riser assessment.