Dynamic Response Analysis and Positioning Performance Evaluation of an Arctic Floating Platform Based on the Mooring-Assisted Dynamic Positioning System

Abstract

The Arctic region is rich in oil and gas resources, but exploitation of resources there is always facing great challenge. Floating offshore platform is considered as a practical choice for oil and gas exploration in the Arctic deep water regions. One of the key technologies is positioning system design under harsh arctic sea loads. In this paper, a comprehensive design of the positioning system is investigated. A coupled numerical model composed of a mooring-assisted dynamic positioning system and the Kulluk platform is established. 16 different positioning combination forms are selected and investigated. The positioning capability of the coupled system is evaluated by analyzing the platform motion response under different environmental loads, including wave, level ice, and broken ice floes. Wave load is calculated using potential flow theory. Computation of ice load is compared with the finite element method (FEM) and discrete element method (DEM). The dynamic analysis of the mooring system is carried out by using the slender finite element method. The control system of dynamic positioning adopts proportional-integral-derivative (PID) control methodology. It is found that a better positioning system design can reduce the offset by more than 50%, including surge, sway and yaw motion. The results of this study will provide a good reference for the positioning system design of an arctic floating production platform.