Coupled Analysis Of Deepwater FPSO And Pipeline

Oil and gas resources are the most important strategy resources for the future development of science and technology. Offshore deepwater even ultra deepwater oil area has become an important field make up the gap between supply and demand of oil and gas. Known as the Real Deep-water Oil Field, Offshore West Africa has been the most attractive investment objective of oil and gas industry for the great oil and gas reserves. Development model of Multi-point moored FPSO+Single Line Offset Risers+Offloading Buoy+Shuttle Tanker has been widespread used for the deep-water oil and gas exploration in offshore West Africa. It is also the necessary content of key technologies for deep-water project. Under this background,this paper has completely finished a series analysis of the FPSO (Floating, Production,Storage and Offloading) offloading system, which has been served in the West Africa.Numerical calculations and model tests are conducted to investigate the coupled hydrodynamic performance of FPSO offloading system in the special environment condition.Firstly, analysis of performance of the FPSO mooring system is performed based on three-dimensional potential flow theory, and then model tests on the turret FPSO mooring system and offloading system are carried out in the basin of offshore engineering, because of the lack of test basin, equivalent truncation designs are carried out on the mooring system of the multi-point moored FPSO. This paper has put forward a project of specific truncation and related calculation formula based on equivalent static and dynamic similarity criteria, the rationality of the equivalent truncated design scheme has verified by comparing the static and dynamic characteristics betwwen truncated mooring system and full mooring system. The model test has completed according to the truncation results, and then the accuracy of the numerical calculations has verified by comparing the results of numerical calculations and model tests, at the same time the basic model has been gived for the following coupling calculation betwwen FPSO mooring system and pipeline systems.Secondly, the time-domain coupled analysis software—Orcaflex has been used to add the FSHR system and OOL system on the base of the verified FPSO mooring system respectively, the calculation of "FPSO mooring system +FSHR system" and "FPSO mooring system+OOL system" has completed with the method of coupling analysis and uncoupling analysis. The impact of existence of the FSHR and OOL system on the original system and the difference between of coupling analysis and uncoupling analysis has been studied, by fully considering the influence of export system to the overall motion responses and mooring system mechanical characteristics of the multi-point moored FPSO. The results show that the existence of the FSHR has little impact on the FPSO mooring system, but the existence of arrangement form and flow has greatly impact on the FPSO mooring system, and the existence of OOL has greatly impact on the FPSO mooring system, so time-domain coupled analysis of the whole FPSO system can not be ignored.