Study on Lateral Vibration Characteristics of a Drill String with Transverse Inertia Effect

Abstract

Drill string vibration is an important factor to influence the normal operation of drilling string system, and lateral vibration is the most complex and most severe vibration form. In order to further understand the lateral vibration characteristics of modes and dynamic for drill string, effectively prevent drill string failure, and improve the service life of drill string, a lateral vibration model of a drill string with transverse inertia effect is established. Then the variation trend of lateral vibration natural frequency of drill string under different conditions is analyzed. The analysis results show that under the influence of transverse inertial effect, the lateral vibration natural frequency of drill string is higher than that without considering the transverse inertia effect. At the same time, the natural frequency gradually decreases with the increase of drill string length; the natural frequency starts to increase and then decrease with the increase of borehole diameter, and the natural frequency gradually increases with the increase of the ratio of external and internal diameter of drill string.