Hydrodynamic Analysis For A Deep-water Semi-submersible Drilling Platform

In the development of the deep-water oil industry, semi-submersible platform is widely used because of its special characteristics: the great performance of stability, the capacious deck area, the preferably payload, the strong ability of drilling and multi-functioned. In deep ocean, the environment is wicked and the physiognomy is complicated. So, talk about the deep-water industry, it is acknowledged as a high-technique, high-investment and high-risk one. Therefore, the responses of the deep-water floating production system are seemed to be important, which are also the key factors in the designs of the platform, the mooring line and the risers.In this paper, to investigate the hydrodynamic behavior of a semi-submersible platform, which is proposed to work in the South China Sea, 1500m depth, nonlinear time-domain coupling numerical method is adopted, considering the notable coupling phenomena between the hull and the mooring system; at the other hand, hybrid method is adopted, model test with a truncated mooring system is fulfilled. Compared the results, we have concluded that:1. Good motion responses characters are performed in operating condition (1 year storm). Horizontal motions are controlled within 7% of the working depth. Max amplitude of heave is 1.65m. Roll and pitch is in the range of±4o. In survival condition (100 year storm), responses are more severe and the max horizontal motion response is about 18% of the depth. Heave motions are exceeded±10m, and roll & pitch amplitude are beyond±7 o . However,...