• 대한조선학회논문집
• /
• 제41권1호
• /
• pp.8-14
• /
• 2004

As the number of offshore structure is glowing in deep waters, there have been increased damages of it. These floating structures in offshore locations exposed to harsh environmental conditions. In recent years, there has been a slowing attention around damages on bow and deck on FPSO caused by waves in steep storm condition. This paper describes a study of the water on deck due to the dynamic behavior of a FPSO with turret mooring system. The nonlinear motions of the FPSO are simulated under external forces due to wave, current, wind, and mooring forces in the time domain. The direct integration method is employed to estimate low frequency drift wave forces. The current forces are calculated by using slow motion maneuvering equations in the horizontal plane. The coefficients of a model for wind forces are calculated from Isherwood's experimental data and the variation of wind speed is estimated by wind spectrum according to the guidelines of API-RP2A.

• 한국해양공학회지
• /
• 제30권4호
• /
• pp.253-259
• /
• 2016

This study demonstrates the result of mooring analysis for five spread-moored FPSOs having different length-to-breadth (L/B) ratios from 4.5–6.5. FPSOs are subjected to four metocean conditions, ones from the Gulf of Mexico (Hurricane/Loop current condition), West Africa, Nigeria, and Brazil Campos Basin, which are amongst the most typical offshore oil and gas fields. With change in design parameters of OBA (Outer bundle angle) and IBA (Inner bundle angle) combinations, a change in the line tension is demonstrated and the OBA-IBA combinations having the smallest line tension are presented for each L/B ratio and sea, respectively. This study is expected to influence the preliminary design layout of an FPSO spread-mooring system as a function of the L/B ratio and metocean conditions.