| During the deepwater testing,the riser is connected with the subsea wellhead through the flexible joint.The tubing string near the flexible joint is prone to damage under the constraints of the riser and the subsea wellhead.This paper based on the structural characteristics of subsea wellhead,blowout preventer,flexible joint deflection and riser deformation,considering the axial force,the lateral stress and bending moment of the string,the differential equation of the tubing string near flexible joint transverse deformation is established.The differential equation would be solved by the numerical method,simultaneous the equation also can be simplified and solved through the analytical method and verified by simulation experiment.The results show that when the axial force is large,the numerical solution of the equation,the analytical solution of the simplified equation and the simulation experiment results can validate with each other.Therefore,the analytical solution of the simplified differential equation can be used to analyze the force and deformation of the local string,which can reduce the workload and meet the engineering requirements. |
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