钻柱涡动特性分析

钻柱绕自身轴线旋转时,绕井眼轴线的转动叫涡动。介绍了钻柱涡动的概念、成因及状态描述,然后通过计算钻柱在不同涡动角速度时摩擦力所消耗的能量,分析了形成不同涡动形式的可能性和主要影响因素。认为钻柱在形成涡动过程中要消耗较多能量,涡动形成后就变成相对稳定的运动状态。认为,减小环隙不会引起钻柱内应力循环频率无限增大。根据钻柱涡动解释了钻铤偏磨和井底多凸图案的成因,并分析了涡动对并斜的影响。

ANALYSIS OF DRILLSTRING WHIRLING

While drillstring rotates along its axis,its rotating along the wellbore axis is defined as whirling.The concept,causes and states were described,while the possibilities and main influences of different types of whirling were analized by working out the force used to overcome the friction under different whirling angular velocity.It is thought more force would be used while forming the whirl,and it becomes static once formed,while decreasing annular could not increase the frequency of alternate stress infinitely.The paper explain the causes of drill collar of f-center wear and bottom hole multi-convex graph based on drillstring whirling,the influence to well deviation was analized too.