Numerical simulation of dynamic buckling response considering lateral vibration behaviors in drillstring

Abstract

Abstract Mechanical behavior of oilwell drillstring coming at the motions of penetrating rock is associated with drilling safety and wellbore quality. A poor performance can be attended by elastic stability loss in a slender drillstring exerting undesired buckling and vibration phenomena in the working process. Devoting to investigating the dynamic buckling behavior is an efficient way to avoid fatigue failure of the drillstring components and enhance drilling rate. A dynamic analysis of the buckling behavior of the entire column considering violent lateral vibrations is presented as a result available. Analytical equations of the drilling system are integrated numerically with finite element method. A virtual contact element implemented between the drillstring and the borehole, in conjunction with Hertzian contact assumption, gives the direct access to calculate the contact force and positions. Lateral deflection, critical length and the effects of drilling parameters and stabilizer on the buckling deformation are captured to experience the realistic buckling response of a typical drillstring in a vertical well. Simulation results indicate that spiral pitch and wave numbers of a nonlinear spiral shape prevailing in the lower zone of drillstring are deeply associated with the cutting force at the bit. Improving a drillstring behavior performance in a real oilfield is observed that this model can assist in evaluating the properties of the working security and buckling resistance with complex boundary conditions.