Search

Tension leg platform (TLP) is a kind of offshore structures for oil or gas exploration in deep-water which has its special feature as partly compliant and partly rigid. Extended tension leg platform (ETLP) is the third generation of TLP which made an improvement on the basis of typical TLP structure. Extended structure is the most notable feature of ETLP which could increase the distance of groups of tethers and magnify the restoring moment. A novel ETLP which consists of four columns and a ring pontoon is proposed in this paper. Four box beams are welded onto each other and formed a ring pontoon. It makes the extended structures to be parts of the pontoons. This design decreases the number of blocks and welds needed for construction, which means the construction cost and period can be reduced, and the structure intensity and fatigue reliability can be enhanced. In this paper, a frequency domain numerical analysis is carried out using HydroD module of SESAM software. The natural periods, the hydrodynamic parameters and motion amplitude response function or response amplitude operator (RAO) of novel ETLP are obtained. The results indicate the natural periods of novel ETLP can satisfy the requirement of API. The novel ETLP has a reasonable hydrodynamic performance, and the asymmetry structure has a negligible impact on yaw performance. The novel ETLP provides an alternative for the structure design of deepwater floating platform, and is significant for launching and optimizing the devising of TLP in future.