深海海况下钻井船钻柱升沉补偿效率分析

Analysis on Compensation Efficiency of Passive Heave Compensation System of Drill Vessel in Deep Sea States

为了合理设计钻柱升沉补偿装置结构,分析了其补偿效率。根据升沉补偿装置物理模型和牛顿第二定律,建立了升沉补偿装置顶驱、大钩和钻柱的三自由度运动数学模型。采用Runge-Kutta算法求解运动模型,获得了设计海况下钻头升沉运动规律。并与1/10升沉补偿装置模型实验结果比对,数值模拟与实验波形吻合。分析了深海海况下,井深、海底刚度以及波浪频率对升沉补偿装置有效补偿窗口的影响。结果表明,深海海况对钻井船升沉补偿效率影响较大。其中:随波浪频率增加,钻柱升沉补偿装置补偿效率由高变低,相当于低频滤波器;不规则波情况下,补偿效率有所降低;井深增加,补偿效率降低;而随海底面刚度增加时,位移补偿效率提高。

To design a passive heave compensation system for drill vessel,the heave compensation efficiency of drill passive heave compensation system was analyzed.In terms of physical model of heave compensation system and the Newton s second law,a mathematical model of the heave compensation system with three-degree-freedom including crown,hook and drill string was built up.The Runge-Kutta algorithm was employed to solve the built mathematical model.The motion of heave compensation system was then achieved and was validated by 1∶10 reduced-scale real model.According to the validated mathematical model of the heave compensation system,the characteristics of the efficient compensative windows under various sea states were detailed.The adjustment of the heave compensative system to different sea stiffness was also discussed.Results show that the efficiency of compensation is dependent on sea states,and that decreases in wave frequencies and sea depth,and increases in case of harder seabed.