Understanding drill string buckling behavior is a significant challenge to the petroleum industry. In this paper, the explicit finite element method implemented in Abaqus software is employed to study the buckling of drill strings for inclined straight wellbores. Classic solutions for the critical buckling length of self-weighted columns as well as critical buckling load for drill pipe inside inclined wellbores are compared to explicit FEA and accurate results are provided by the finite element based predictions. The effect of different inclination angles and string effective weight due to the buoyancy effect has been studied and the results for sinusoidal and helical buckling are compared to analytical results and experimental data in the literature. The theoretical predictions for different inclination angles agree with the simulations. Theoretical buckling load of inclined drill strings approaches zero by decreasing the effective weight of a floating drill string. However, the results of finite element simulations show that significant buckling load would still exist for very low drill string effective weight. These results are confirmed by experimental results provided by other researchers. Overall, the efficacy of using explicit finite element methods to model drill string buckling behavior is demonstrated.
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