Towing Analysis of Multi-Cylinder Platform for Offshore Marginal Oil Field Development

Abstract

As the development of offshore marginal field becomes a heated topic, various design selections of offshore platform have already been put forward in the community such as Sevan SSP, IQFP-FPSO, octagonal FPSO or sandglass-type FDPSO. In this paper, a new Muliti-Cylinder FPSO (MCPSO) with section pile foundation is proposed for developing offshore marginal field in South China Sea. And the structure design in detail has been described. The MCPSO consists of six cylindrical concrete tanks and six suction piles. The suction piles can be raised up during platform towing process. Considering the effects of tanks and piles on the towing stability, both intact and damage stability analysis of MCPSO were performed under different towing conditions. The influence of ballast ratio, towing direction and different damaged modes on the towing stability is analyzed. The results indicate that the MCPSO has the characteristics of self-installation, movable, reusable and so on, which is suitable for the development of marginal oil field. The MCPSO filled with 40% seawater in ballast tank and towed in 90 direction has the best intact and damage stability characteristic.