桩基建模方法对自升式钻井平台动力响应的影响

Influence of Footing Model on Dynamic Response of Jack-up Drilling Platform

随着海洋油气开采作业水深的不断增加,海洋平台固有周期随之增加,易与相同周期成分的波浪产生共振,因此对平台动力响应特性研究是非常必要的,而桩基模型在平台动力响应分析中发挥着关键作用。以某400 ft自升式钻井平台研究对象,基于等效建模的思想,分别建立了固支桩基、铰接桩基、线性弹簧桩基及非线性弹簧桩基4种有限元模型,并对其进行静力分析、模态分析及瞬态动力学分析。通过对比所得振动周期、动力放大因子及波流惯性力,得出弹簧桩基模型在平台动力响应分析中的有效性及合理性结论。

With the continuous increase of offshore oil and gas mining depth, the natural period of platform increases, and the platform resonances easily with the same period wave. So it is very necessary to study the characteristics of dynamic response, and footing model plays a key role in dynamic response analysis of platform.Taking a 400 feet jack-up drilling platform as object, the four finite element models（FEMs） is established with different footing assumption including fixity, pinned, linear spring, and non-linear spring. Then, a series of static analysis, modal analysis and transient dynamic analysis are performed for the four models. By comparing vibration period, dynamic magnification factor and wave-current inertia force, it is concluded that the linear spring footing model is an effective and reasonable method in dynamic analysis.