环空钻柱三维二重非线性动力学问题的研究

通过对大挠度钻柱受力变形特点及其环空旋转状态下与井壁接触机理的分析，根据动力学原理，建立和进一步完善钻柱与井壁动态摩擦接触模型．根据有限元理论，提出了Ｗｉｌｓｏｎ－θ法与Ｎｅｗｔｏｎ－Ｒａｐｈｓｏｎ法相结合的模式，解决钻柱二重非线性动力学问题．计算分析结果说明，文中理论模型是可行的，不仅更完善，而且更简便；动态非线性效应分析得到了与静态分析相似的结论；钻柱与井壁各种接触形式或并存或交替都有可能；转速较高时动态影响不容忽视．

A STUDY OF TRIDIMENSIONAL DOUBLE NONLINEAR DYNAMICS OF DRILLSTRING IN ANNULUS

Based on the analysis of forces and deformations of drillstring with large deflection and intermittent contacts with the well wall,the model of the dynamic frictional contact is improved. Solving the double-nonlinear dynamic problem of drillstring by combinning Wilson-θ method with Newton-Raphson method is developed. The computations show it is possible that various kinds of contact exist togather or alternatively, and that dynamic analysis must be done in higher revolution speed.