... of whirl and HFTO at the bit. The excitation of HFTO can be attributed to a velocity-dependent characteristic of the cutting torque. A model that incorporates the superposition of lateral and torsional movement at the bit is used to calculate the velocity-dependent bit torque based on three components...

..., with under-gauged stabilisers and a rotary tool disconnecting torque transmission from the stuck point. To address the above-discussed challenge of a differentially stuck pipe, a large-scale experimental rig was designed, manufactured, installed and instrumented to investigate the whirling motion of a shaft...

... the system. Performance data is also provided to show the impact on operations. Performance improvements have varied by hole size, but range from 60 – 380%. efficiency upstream oil & gas strength driller redesign whirl wob real time system drilling operation axial vibration stick slip...