钢悬链线立管动力响应的参数分析与管段重量优化研究

发布时间：2018-08-28 15:24

【摘要】：钢悬链线立管作为一种新型立管型式,是深水油气开发的首选立管。钢悬链线立管在位期间,所处的环境非常复杂恶劣,承受波浪、海流、上端浮体的运动、下端海床摩擦等作用,这些荷载共同作用使立管动力响应十分复杂。本文利用ABAQUS有限元分析软件,对钢悬链线立管整体进行建模。根据垂向管土相互作用的P-y曲线模型及侧向管土相互作用的三线性模型,在立管触地段建立垂向及侧向的非线性弹簧,模拟立管与海床的相互作用,并施加波浪海流荷载、浮体运动作用,计算钢悬链线立管进行整体动力响应。在此基础上,通过改变海流方向、初始悬挂角、内径、壁厚以研究这些参数对立管动力响应的影响。结果表明,触地点附近处的时程应力对海流作用方向较为敏感,当立管作用方向与立管所在平面为同一平面上时,应力幅值较大;随着悬挂角增加,立管时程最大应力出现位置向锚固点移动,整体应力最大值减小,立管悬挂段和流线段位置处的时程最大应力随悬挂角的增大而增大;随着壁厚的增加,立管各处的时程最大应力减小;立管管径变化对动应力影响不大。此外,本文还通过改变立管不同管段的涂层密度来分析研究管段重量变化对钢悬链线立管动力响应的影响。通过分析得出增大悬垂段管段重量或减小初始触地段重量可使立管应力减小,而改变远离触地点的底部流线段的外部涂层密度不影响应力。沿立管弧长段存在一个特殊位置,将其作为不同涂层分布的分界处,可以显著减小立管最大动应力;将该分界处向悬挂点或触地点移动而偏离该位置都将增大立管最大动应力,在进行管段重量优化时需要特别注意该特殊位置。最后通过对比重量优化前后立管动应力表明采用管段重量优化可以明显改善钢悬链线立管的整体动力特性,作为提高钢悬链线立管可靠性的一项途径。
[Abstract]:As a new type of riser, steel catenary riser is the preferred riser for oil and gas exploitation in deep water. When the steel catenary riser is in position, the environment is very complex and harsh, and it bears the actions of wave, current, upper floating body, bottom seabed friction and so on. These combined loads make the dynamic response of riser very complex. In this paper, ABAQUS finite element analysis software is used to model the whole steel catenary riser. According to the P-y curve model of vertical pipe-soil interaction and the trilinear model of lateral pipe-soil interaction, vertical and lateral nonlinear springs are established in the contact section of riser to simulate the interaction between riser and seabed, and the wave current loads are applied. The whole dynamic response of steel catenary riser is calculated by floating body motion. On this basis, the influence of these parameters on the dynamic response of the tube is studied by changing the direction of the current, the initial suspension angle, the inner diameter and the thickness of the wall. The results show that the time-history stress near the contact site is sensitive to the direction of current action. When the action direction of riser is on the same plane as the plane of riser, the stress amplitude is larger, and with the increase of suspension angle, The maximum stress of the vertical pipe moves to the anchoring point and the maximum stress of the whole body decreases. The maximum stress of the riser increases with the increase of the suspension angle and the thickness of the wall, and the maximum stress of the vertical pipe increases with the increase of the suspension angle, and the maximum stress of the vertical pipe increases with the increase of the wall thickness. The maximum stress of the riser is decreased and the diameter of the riser has little effect on the dynamic stress. In addition, the influence of weight variation on the dynamic response of catenary riser is studied by changing the coating density of different sections of riser. It is concluded that the stress of the riser can be reduced by increasing the weight of the tube or decreasing the weight of the initial contact section, but the stress is not affected by the change of the external coating density of the flow line at the bottom far from the contact point. There is a special position along the long segment of vertical tube arc, and the maximum dynamic stress of riser can be significantly reduced by using it as the boundary of different coating distribution, and the maximum dynamic stress of riser will be increased if the boundary is moved to the suspension point or contact point, and the maximum dynamic stress of riser will be increased when it deviates from this position. Special attention should be paid to this special position when optimizing the weight of the pipe segment. Finally, by comparing the dynamic stress of the riser before and after the weight optimization, it is shown that the overall dynamic characteristics of the catenary riser can be obviously improved by using the optimization of the weight of the steel catenary as a way to improve the reliability of the steel catenary riser.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TE95;P742

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