可控偏心稳定器钻具组合弹性稳定性研究及其应用

可控偏心稳定器是旋转导向钻井技术中的核心工具之一,结合钻井作业的实际情况,对可控偏心稳定器钻具组合的弹性稳定性进行了研究和分析。运用纵横弯曲梁的理论,建立了管柱在纵横弯曲条件下的挠曲变形方程;运用能量法建立了受压管柱在旋转状态下的弹性变形方程,并且得到了临界钻压的求解方法;通过综合考虑井斜角、钻具自重、扭矩、转速、钻具的几何尺寸、钻压等6个重要因素对管柱临界失稳的影响,推导出了临界钻压的表达式,为合理使用好旋转导向钻井工具,特别是可控偏心稳定器心轴的合理设计和安全使用提供了理论依据,对现场钻井作业有积极的指导意义和借鉴作用。

Study on the elastic stability of bottom holes assembly with controllable eccentric stabilizer and its application

The controllable eccentric stabilizer is one of important tools in rotary navigation drilling.According to the actual drilling operations,the study and analysis are carried out on the elastic stability of bottom holes assembly with controllable eccentric stabilizer.The flexural deformation equation is formulated for pipe string under vertical and horizontal bending condition based on vertical and horizontal bending beam theory.Elastic deformation equation is established by the energy method for the compressed pipe string under the rotary condition and the method for solution of critical weight on bit has been found.Considering six important factors,including the hole deviation angle,dead weight,torque and rotary speed of drilling string,size of tools and weight on bit,can lead to the critical stability loss of pipe string,the expression for critical weight on bit is derived,which offers the theoretical evidences for proper use of rotary navigation drilling tool,especially for rational design and safety use of axial of controllable eccentric stabilizer,and has the guiding significance and reference for the field drilling operation.