Dynamic gangway responses between TLP and semi-submersible platform during tender-assisted drilling

摘要

Numerous tender assisted drilling (TAD) platforms are built to offer comfortable accommodation for crews, on-site construction, and maintenance for production platforms. Two platforms are usually connected via a telescopic gangway, the safety and feasibility of which are crucial during personnel transfer operations. In this paper, the dynamic gangway responses of a TLP-TAD coupled system are investigated numerically and experimentally. The numerical model is established in the frequency domain by using 3D multi-body diffraction/radiation wave theory; this is followed by time domain simulation to consider the second-order drift loads and the non-linear characteristics of the mooring systems. Experiments are performed to verify the numerical model. The connection point between the gangway and platform is simplified as a joint, from which gangway responses can be derived by the global motions of the platforms. Both single-body and multi-body cases are studied under different headings for comparison. The multi-body hydrodynamic interaction is not significant in this paper, while the sway-surge and sway-heave coupling in addition to the wave shielding effect are induced. The results of gangway extension and rotation show that the dominant degree of freedom (DOF) of global motion for gangway responses is identical under different headings. The extreme value predictions of gangway responses are also performed based on Weibull distribution, and extreme sea conditions are obtained.