Study On Hybrid Model Test For Hydrodynamic Performance Of FPSO

There are very abundant oil and gas resources in the deep-water areas of the whole world.Since the 1970 s,the deep-water oil and gas exploration has been developed rapidly and spread all over 18 deep-water basins in the world’s oceans.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.As background to this article,study on hybrid model test for global performance of deep-water multi-point moored FPSO is conducted in swell and wind wave in offshore West Africa.Firstly,equivalent truncation designs are carried out on the mooring system and offloading system of the multi-point moored FPSO.An equivalent water depth and width truncated design based on equivalent static loading methods for FPSO mooring system is investigated which can better meet the environment direction from 0 to 180 degrees;An equivalent truncated design based on equivalent static and dynamic loading methods for FPSO offloading system is also studied.Specific truncation method is proposed to support the hybrid model test.Secondly,model tests on the turret FPSO mooring system and offloading system are carried out in the basin of Harbin Engineering University,which include free decay tests of FPSO,RAO tests under white noise wave,flow resistance tests,wind resistance tests,tests of FPSO global response under irregular and tests of FPSO coupled with offloading system.Test results provide the basis for time-domain coupled analysis.Thirdly,according to the test results,AQWA software is used to reconstruct the model test results to identify the key hydrodynamic parameters and get the correct numerical model.On this basis,full-depth model is built with AQWA to predict the FPSO motion response and mooring tension as the final results.It is found that numerical reconstructed and extrapolated results agree well with model test results at truncated water depth,which prove the truncation designs and tests are reasonable and proper.Finally,based on the model tests and numerical calculation,FPSO vertical motions response and the impact of offloading system on FPSO global response are discussed.The results show that FPSO vertical motions are dominated mainly by swell;Offloading system has an even greater impact on FPSO global response and mooring tension,so time-domain coupled analysis of the whole FPSO system can not be ignored.In conclusion,study on hybrid model test for global performance of deep-water FPSO is carried out in this paper to get the regulation of FPSO global response and mooring tension.Theoretical support and advices are provided for the deep-water oil and gas exploration in offshore West Africa.