Mooring analysis for a whole TLP with TTRs under tendon one-time failure and progressive failure

Abstract In deepwater oil and gas field development, a Tension Leg Platform (TLP) consists of a hull, tendons, and top tension risers (TTR). When one or more tendons failure due to extreme sea state, a TLP will be under the working condition which is very different from its design condition, showing structural instability and transient effect. To enhance the safety and global stability of whole TLP system, obtaining failure consequences is necessary. By 3D potential flow theory and panel element method, a series of mooring analyses are performed for the target TLP to predict its coupled hydrodynamic response after tendon one-time failure and, in particular, during progressive failure of several tendons. Different directions of environment load that including extreme wind, wave and current and tendon failure positions are considered. In the results, the motion response of the hull, the force from residual tendons and TTRs are presented.