This study focuses on the nonlinear lateral vibration of drillstring in curved wells. One of the most important features of this work is that the drillstring dynamics in curved wells (including both vertical, deflecting and horizontal well structures) are modeled and presented in actual drilling engineering scale. In the proposed model, beam finite element (FE) method is employed to calculate the drillstring dynamics in curved wells. The model is solved by the generalized-$\alpha$ method and verified by reproduction of the field data. The model has coupled the lateral, torsional and longitudinal vibrations of the drillstring, while we only pay our attention to the nonlinear lateral vibration of drillstring in curved wells. The efficient length of lateral vibration of a field curved well is firstly proposed, and the influences of rotation speed, weight on bit (WOB), coefficient of friction (COF) and stabilizer (STB) on the lateral vibration of drillstring in curved wells are discussed.

本研究重点研究弯曲井中钻柱的非线性横向振动。这项工作最重要的特点之一是弯曲井（包括垂直井、偏转井和水平井结构）中的钻柱动力学以实际钻井工程规模进行建模和呈现。在所提出的模型中，梁有限元（FE）方法被用来计算弯曲井中的钻柱动力学。该模型由广义 -$\alpha$方法并通过再现现场数据进行验证。该模型耦合了钻柱的横向、扭转和纵向振动，而我们只关注弯曲井中钻柱的非线性横向振动。首次提出了现场弯曲井横向振动的有效长度，研究了转速、钻压(WOB)、摩擦系数(COF)和稳定器(STB)对弯曲井钻柱横向振动的影响讨论。