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Estimation of the drill bit angular velocity using accelerometer measurements and extended Kalman filters

In this paper, an extended Kalman filter model is proposed to estimate the angular velocity of a drilling shaft based on the accelerometer measurements of a downhole recording tool mounted on the drill rod. The method allows tracking the severity of torsional vibrations in real-time. The results outline the advantages of the proposed method in particular its ability to capture events of backward rotation known to be very detrimental to the life of drill bits.