浮式平台运动对深水钻井隔水管安装过程横向动力特性的影响分析

Analysis of the effect of floating platform motion on the lateral dynamic characteristics of deepwater drilling riser during installation

深水钻井隔水管安装过程中的力学特性对安全高效安装作业具有重要影响。考虑顶部浮式平台漂移运动的影响,建立隔水管安装过程横向动力特性分析模型和控制方程,利用有限差分法对控制方程进行数值求解,讨论顶部浮式平台的静偏移、漫漂幅值和漫漂周期等对隔水管安装过程横向动力特性的影响。结果表明:深水钻井隔水管安装过程中,横向位移最大值出现在隔水管底部,弯矩与应力的最大值出现在隔水管顶部靠近海面的位置;在一个平台漫漂周期内,隔水管底部横向位移的最大值与顶部弯矩的最大值出现在同一时刻,顶部应力的最大值出现时刻滞后于顶部弯矩的最大值出现时刻;平台静偏移主要影响隔水管安装过程中的横向位移,二者呈正相关关系;平台漫漂幅值是影响隔水管安装过程横向动力特性的主要因素,随平台漫漂幅值的增大,隔水管横向位移、弯矩和应力增大;平台漫漂周期对弯矩影响较小,对横向位移和应力无明显影响。该结果对深水钻井隔水管安装过程具有工程指导意义。

The mechanical characteristics of deepwater drilling riser during installation have an important impact on its safe and efficient installation.Considering the effect of the dynamic drift of the top floating platform during riser installation,the lateral dynamic characteristic analysis model and control equation during riser installation have been established.The control equation has been numerically solved by the finite difference method,and the effects of the static offset,drift amplitude and drift period of the top floating platform on the lateral dynamic characteristics during riser installation have been discussed.The results show that during the installation of deepwater drilling riser,the maximum value of lateral displacement appears at the bottom of riser,and the maximum value of bending moment and stress appears at the top of riser near the sea surface.In a platform drift period,the maximum lateral displacement at the bottom of the riser occurs at the same time as the maximum bending moment at the top,and the maximum stress at the top lags behind the maximum bending moment at the top.Platform static offset mainly affects the lateral displacement during riser installation,and the static offset and lateral displacement are positively correlated.The amplitude drift of platform is the main factor affecting the lateral dynamic characteristics of riser installation.With the increase of the amplitude drift,the lateral displacement,bending moment and stress of riser increase.The drift period of the platform has little effect on the bending moment,and has no obvious effect on the lateral displacement and stress.This research is of engineering guiding significance for the installation process of deepwater drilling riser.