套管柱-钻井液-水泥浆耦合系统横向振动特性分析

振动固井工程中利用激振器对套管柱进行激励使其达到共振效果,以此来提高固井质量,这就需要对套管柱-钻井液-水泥浆耦合系统进行模态和振动特性分析。针对这一问题,建立了套管柱-钻井液-水泥浆流固耦合模型,利用有限元分析软件ANSYS Workbench进行模态分析和振动响应分析,采用单因素分析法对其固有频率影响因素进行仿真分析。结果表明,套管柱在流固耦合状态下各阶固有频率低于无耦合时的情况,相同阶数下,模态振型基本相似；耦合系统横向振动频率随长度的增加而减小,随钻井液密度和水泥浆密度的变化较小,随温度的升高而降低；在较大激振力下,底端振幅较大。实际固井作业中,可以发挥大激振力和低频组合方式产生的共振效果,来提高固井质量。

Analysis of Lateral Vibration Characteristics of Casing-Drilling Fluid-Cement Slurry Coupling System

In the vibrating cementing project, the exciter is used to excite the casing string to achieve resonance effect, thereby improving the cementing quality. This requires modal and vibration characteristics of the casing string-drilling fluid-cement slurry coupling system. analysis. Aiming at this problem, a fluid-solid coupling model of casing-drilling fluid-cement slurry was established. The modal analysis and vibration response analysis were carried out by finite element analysis software ANSYS Workbench. The influence factors of natural frequency were simulated by single factor analysis. analysis. The results show that the natural frequencies of the casings in the fluid-solid coupling state are lower than those without coupling. Under the same order, the mode shapes are basically similar; the transverse vibration frequency of the coupled system decreases with the increase of the length. The change of drilling fluid density and cement slurry density is small, and decreases with the increase of temperature; under the larger excitation force, the bottom end amplitude is larger. In the actual cementing operation, the resonance effect generated by the combination of the large exciting force and the low frequency combination can be exerted to improve the cementing quality.