Instrumented saver sub for stick-slip vibration mitigation

摘要

A drilling rig apparatus is disclosed for mitigating stick-slip using a saver sub that is compatible with different top drives. The saver sub includes a smart material adjustable whenever a stand is added to the drill string to have different spring characteristics to generally match the impedance of the top drive to the impedance of the drill string. The saver sub also includes a magneto rheological fluid that is adjusted whenever a stand is added to the drill string to compensate for the changed characteristics of the drill string. The damping constant implemented by the MR fluid enables the saver sub to absorb stick-slip vibrations at the top drive. Each time that a stand is connected to the drill string, the spring and damping constants may be updated to accommodate the changing characteristics of the drill string.