Active Damping of Torsional Drillstring Vibrations With a Hydraulic Top Drive

Summary This paper describes the development and field testing of a new active-damping system to eliminate "stick/slip" torsional drillstring vibrations. The system controls the energy flow through a hydraulic top drive and makes the top drive react as a tuned vibration damper. The control algorithm, outlined in the paper, was implemented in software in the electronic control system for the pump unit of the top drive. Dedicated workshop testing allowed for a rapid installation at the rigsite. The system was field tested in a deep exploration well in the Barents Sea and contributed to excellent coring performance by eliminating torsional vibrations while coring hard limestone.