基于Timoshenko梁理论的深水油气井套管柱地震响应分析

海洋表层软土对深水油气井套管柱井身结构的稳定性有着重要影响，尤其地震发生时，会在软硬土层交界面处管柱截面产生很大的弯矩和剪力。依据桩基的动力响应理论，引入回传射线矩阵法，建立了适于深水油气井套管柱的地震响应分析模型。模型中将组合套管柱等效为变截面Timoshenko梁，分别从表层软土的剪切波速和厚度分析，探讨了套管柱在软硬土层交界面处弯矩和剪力幅值的变化规律，从而为海洋工程中套管柱的施工、设计和安全性评估提供一定的参考和指导作用。

Seismic response of casing string in deepwater oil and gas well based on theory of Timoshenko beam

The soft surface layer has great influence on the stability of subsea casing string in deepwater oil and gas well. Especially, the earthquakes can cause a great bending moment and large shear force on the cross section of casing string. An analytical model for the seismic response of subsea casing string is established on the basis of pile foundation theories and method of reverberation-ray matrix. The casing string is asummed to be a Timoshenko Beam of variable cross section. The bending moments and shear forces of casing string at soft and hard soil cross sections are discussed from the aspect of the shear velocity and thickness of soft surface layer. The results of this work provide reference and guidance for the engineering construction, design and security assessment in practice.