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隔水管是海洋钻井工程中的必要设备。在深水环境下,隔水管的疲劳失效问题普遍存在,隔水管的强烈振动是导致其失效的主要原因之一。本文采用微元法,得到了隔水管在各种载荷作用下的横向振动规律及其横向振动的固有频率的分布规律,进一步分析了各种因素对隔水管横向振动固有频率的影响。结果表明:隔水管的长度增加时,固有频率减小;随着顶部张力比的增加,隔水管的横向振动的固有频率也增加;随着壁厚的增加,隔水管横向振动的固有频率逐渐降低;而随着钻井液密度的增加,隔水管横向振动的固有频率增加;海水的存在使隔水管的横向振动固有频率降低。该研究有利于避免隔水管在使用过程中出现强烈的共振现象,为减小隔水管的失效提供了理论依据。
The riser is a necessary equipment in marine drilling engineering. Under deep water environment, the problem of fatigue failure of riser is widespread, and the strong vibration of riser is one of the main causes of its failure. In this paper, the law of transverse vibration and the natural frequency of transverse vibration of riser under various loads are obtained by using the method of differential equations. The influence of various factors on the natural frequency of transverse vibration of riser is further analyzed. The results show that the natural frequency decreases when the riser length increases and increases with the increase of the top tension ratio. As the wall thickness increases, the natural frequency of the riser transverse vibration gradually decreases The inherent frequency of riser transverse vibration increases with the increase of drilling fluid density, and the natural frequency of riser transverse vibration decreases with the existence of seawater. The study is conducive to avoid the phenomenon of strong resonance of riser in use, which provides a theoretical basis for reducing the failure of riser.