Excess vibration of the drillstring is a serious concern in drilling because it accelerates the fatigue process and reduces the life of the bottomhole assembly (BHA). In extreme cases, excess vibration can lead to premature failure of the equipment. Drillstring vibration can also produce borehole washout, increase the risk of sticking pipe, and reduce the rate of penetration (ROP). Although weight-on-bit (WOB) and rotary speed are the primary parameters used to control vibration, the study of other parameters, such as ballooning, contact and frictional forces between the drillstring and the wellbore, and the finite displacement of the drillstring may provide additional tools and methods for controlling and minimizing drillstring vibration during drilling. The dynamic behavior of an active drilling assembly is complex to simulate and analyze, and finite element numerical models are used to investigate the influence of various factors on drillstring vibration.
The objective of this study is to derive additional options that will improve ROP by providing more flexibility in BHA design than those provided by traditional WOB-rotary speed methods. We focus on the influence of mud density, borehole inclination angle, and the choice of drilling fluid rheology model on the drillstring vibration.