A Parametric Study on the Innovative Coupling Arm Connecting the Coupled TAD-TLP

Abstract

Two body marine systems, like a Tender Assisted Drilling (TAD) vessel coupled with a floating Dry-Tree Unit (DTU), have become very common in offshore operations. One of the unavoidable challenge we have to cope with is the connection between the TAD and DTU should make sure the TAD does not drift away from the platform and also avoid the possible collision in case of a harsher environment. The objective of this study is to understand the hydrodynamic interactions between the two coupled floating bodies and improve the devising of the innovative connection system. In this study, an innovative rigid connection system, the coupling arm is applied to connect the TAD and a DTU, in this case, a Tension Leg Platform (TLP). The whole system is modelled by the commercial software HARP. A comprehensive parametric study on the pretension and the nominal length of the coupling arm is carried out. The hydrodynamic analysis of the coupled TAD-TLP system elucidates the interactions between the two bodies. The chosen combination of the coupling arm pretension and the nominal length will determine the required stroke range and maximum forces needed to design the innovative coupling arm for safe operations. © The Authors, published by EDP Sciences, 2018.