The Dynamic Response And Fatigue Analysis Of SCR Considering Pipe-Soil Interaction

China has a vast continental shelf and owns rich deepwater oil, but due to thelack of technologysupport and fund, the deepwater soil hasn’t been explored well. Ashydrocarbon production has been moving into deep and ultra-deep waters, many newkinds of equipments have been developed for deepwater oil exploration, as a typicalpipeline equipment in deepwater oil exploration, the steel catenary riser (SCR) isplaying an important role in China’s deepwater oil exploration.As the SCR is under the hostile sea environment, the load it bears is complex andchangeable. In this paper, the load acting on the SCR is introduced and thecorresponding fatigue life is analyzed as well.First the mechanism of pipe-soil interaction of SCR in the touchdown zone andthe common method for the pipe-soil interaction analysis will be introduced,according to the advantages and disadvantages of each method, the proper methodwill be chosen for the subsequent analysis as well as the dynamic analysis of SCR inthe touchdown zone under different conditions.Next the dynamic and fatigue analysis of the whole SCR under sea loadconsidering the pipe-soil interaction in the touchdown zone will be performed. It isobvious that the touchdown point and nearby as well as the hanging point are the hotspot in the fatigue damage analysis of SCR. The effect of soil suction and soilproperty on the fatigue life of SCR is also investigated.Moreover, the mechanism of vortex induced vibration (VIV) of SCR and someimportant parameters in the VIV are mentioned. Based on the analysis software ofVIV, SHERA7, several parameters that have significant influence on the fatiguedamage life of SCR such as top tension, elastic modulus and the pipe diameter areinvestigated.Finally, the fatigue crack growth of SCR is introduced briefly. Based on thesingle crack growth curve model proposed by Huang Xiaoping, the crack growth analysis on different part of the SCR are performed under different conditions such asthe soil suction and soil property, the hysteresis of overload on the crack growth ofSCR is performed as well.