Research on Stick-slip Vibration Control Method of Drill String

The stick-slip vibration generated during drilling can easily lead to drilling accidents and reduce the drilling efficiency. By analyzing the mechanism of the stick-slip vibration, a motion equation of drill string is established; The combination of top drive and bottom hole assembly is equivalent into lumped mass blocks, a two lumped mass spring damping vibration model is built, the simulation results show that the drill string model can effectively simulate downhole stick-slip vibration. Aiming at the problem that it is difficult to obtain the drill bit speed, a kind of proportion integration differentiation control algorithm based on the state observer is designed and simulated, the results show that the state observer can effectively estimate the drill bit speed, and the control method can effectively suppress the drill string stick slip vibration. Based on the theory of similarity, the stick-slip vibration experimental device is built and studied, the experimental results show that the control algorithm is effective and has a good control effect on the downhole stick-slip vibration. The stick-slip vibration control method of drill string provides a theoretical basis for top drive control in drilling engineering and has important engineering application value.