State of the Art in New Semisubmersible Platform Concepts

The semisubmersible platform (Semi) shows superior performance to the Spar, TLP and FPSO owing to its unique and reasonable structure and shape, and thus is one of the most vital and promising equipment for deepsea oil and gas development. Nevertheless, its inherent disadvantages have been gradually revealed through six decades of extensive engineering practices and in-depth research. Much innovative work has been carried out during recent two decades to improve its overall performance and maximize its safety and operability to utilize it in supervisor ways. Firstly, the shape features of a conventional Semi and the operation requirements in different phases during the whole life cycle of a Semi were summarized. Then, the factors affecting the stability and the motion performance of a Semi and their internal relationship were studied according to the principles of hydrostatics and hydrodynamics. After that, representative innovative conceptual Semi designs in the academic papers and the patent documents were reviewed. Finally, the directions for further innovation and growth of the Semi were predicted. This paper aims to provide some inspiration and reference to the experts and scholars engaged in deepwater offshore field development and innovative research on the floating structures.