Abstract: Systems and methods for damping torsional oscillations of downhole systems are described. The systems include a downhole drilling system disposed at an end of the downhole system in operative connection with a drill bit. A damping system is installed on the downhole drilling system, the damping system having at least one damper element configured to dampen at least one HFTO mode. At least one mode-shape tuning element is arranged on the drilling system. The at least one mode-shape tuning element is configured and positioned on the drilling system to modify at least one of a shape of the HFTO mode, a frequency of the HFTO mode, an excitability of the HFTO mode, and a damping efficiency of the at least one damper element.

Abstract: A method of estimating a stability value of a rotating downhole component includes rotating the downhole component at a varying first rotary speed, the varying first speed having a plurality of first rotary speed values, and identifying an oscillation of the downhole component. The method also includes acquiring measurement data from a sensor, the measurement data indicative of a measured parameter related to the oscillation of the downhole component at the plurality of first rotary speed values, and estimating the stability value of the rotating downhole component as a function of an operational parameter based on the acquired measurement data.

Abstract: Systems and methods for damping vibrations of downhole systems are described. The systems include a downhole component configured to be disposed downhole and a shock-damping system at least one of on or in the downhole component, the shock-damping system configured to reduce torsional oscillations of the downhole component by imparting a selected shock to the downhole component. The selected shock is selected to generate damping of the torsional oscillations of the downhole system.

Abstract: A method of estimating a stability value of a rotating downhole component includes rotating the downhole component at a varying first rotary speed, the varying first speed having a plurality of first rotary speed values, and identifying an oscillation of the downhole component. The method also includes acquiring measurement data from a sensor, the measurement data indicative of a measured parameter related to the oscillation of the downhole component at the plurality of first rotary speed values, and estimating the stability value of the rotating downhole component as a function of an operational parameter based on the acquired measurement data.

Abstract: Systems and methods for damping torsional oscillations of downhole systems are described. The systems include a downhole drilling system disposed at an end of the downhole system in operative connection with a drill bit. A damping system is installed on the downhole drilling system, the damping system having at least one damper element configured to dampen at least one HFTO mode. At least one mode-shape tuning element is arranged on the drilling system. The at least one mode-shape tuning element is configured and positioned on the drilling system to modify at least one of a shape of the HFTO mode, a frequency of the HFTO mode, an excitability of the HFTO mode, and a damping efficiency of the at least one damper element.