考虑平台作用的顶张式立管动力分析

Dynamic Analysis of Top-Tensioned Riser on Platform

上层浮式平台的运动幅度比固定式平台大,对立管的影响更明显。为了解平台对顶张式立管动力的影响,提出一种动力分析方法。在一定的条件下建立立管的数学模型,采用软件Tube2D对平台和立管进行动力响应和弯曲应力分析,得到考虑平台作用的立管扶正器布置间距参数的敏感性和立管弯曲应力的变化。结果表明:对于考虑平台作用的立管模型而言,内套管与油管在立管上部更容易发生碰撞,从避碰的角度考虑,应适当减小立管上部扶正器的布置间距;各层立管的弯曲应力按弯曲刚度之比分配的结果与实际计算结果不符,应根据耦合立管模型的计算结果对各层立管进行强度校核。

The motion amplitude of a semi-submersible floating platform is large and has noticeable effects on the riser on the platform.The modeling and the dynamic analysis of the top-tensioned riser are studied.The dynamic response of the riser to the motion of the platform and the bending stress in the riser are researched.The relation between bending stress in the riser and centralizer spacing is studied.The sensitivity of the stress to centralizer spacing is analyzed.The research shows that the spaces between centralizers should be smaller at upper part of the riser to prevent the inner casing from striking the oil pipe because of platform motion.The model-calculated bending stress in individual pipe is different from that obtained by distributing the force on basis of bending stiffness of pipes.The latter is incorrect and should not be used.