Short-Term Extreme Value Prediction for the Dynamical Responses of a Semi-Submersible Platform in Harsh Environment

Deep-sea platforms play a crucial role in the exploration of oil and gas resources. Ensuring the safety of semi-submersible platforms in challenging marine environments is of paramount importance. Consequently, this research is dedicated to the estimation of extreme values for motion responses and the mooring loads of a deep-water semisubmersible platform in the South China Sea. Specifically, numerical simulations are carried out by using commercial software, and the accuracy of the numerical results is verified with experimental data. To assess the safety of mooring systems with multipoint configurations under extreme sea conditions, the environmental contour method (ECM) is applied to select the most severe sea state. For a given sea state, short-term extreme value analysis is performed by using the average conditional exceedance rate (ACER) method. Finally, an analysis of the extreme value predictions is performed in compliance with relevant regulations to evaluate the safety of the mooring system.