Abstract: A method for controlling vibrations in a drilling system, the drilling system including an elongate body extending from surface into a borehole formed in an earth formation, and an associated drive system for driving the elongate body, the drive system comprising a torque controller, the method comprising obtaining a model of the drilling system; obtaining at least one input parameter for the model that relates to an uphole parameter of the drilling system; operating the drive system to provide a drive torque to the elongated body; obtaining at least one output parameter from applying the model using the at least one input parameter, the at least one output parameter including at least one modelled downhole parameter of rotational motion; using the modelled downhole parameter of rotational motion in the torque controller for determining an adjustment to the drive torque, so as to control vibrations; as well as a drilling system comprising a torque controller, which torque controller is adapted to use the mode

Abstract: A control system and method for limiting vibrations in a drilling system, including a drill string and a drive system for providing drive torque for rotating the drill string at a reference frequency. The control system includes a sensor module for determining an uphole parameter of the drilling system, a model module provided with a model of the drilling system and adapted to provide modeled parameters of the drilling system using the drive torque as an input, a model gain module for providing a model gain vector to the model module in response to one or more of the modeled parameters and the drive torque. The model gain vector enables the model module to update the model thereby obtaining an updated model, and a control module provides a torque correction factor to the drive system depending on the modeled parameters, the uphole parameter, the reference frequency, and the drive torque.

Abstract: A method for controlling vibrations in a drilling system, the drilling system including an elongate body extending from surface into a borehole formed in an earth formation, and an associated drive system for driving the elongate body, the drive system comprising a torque controller, the method comprising obtaining a model of the drilling system; obtaining at least one input parameter for the model that relates to an uphole parameter of the drilling system; operating the drive system to provide a drive torque to the elongated body; obtaining at least one output parameter from applying the model using the at least one input parameter, the at least one output parameter including at least one modelled downhole parameter of rotational motion; using the modelled downhole parameter of rotational motion in the torque controller for determining an adjustment to the drive torque, so as to control vibrations; as well as a drilling system comprising a torque controller, which torque controller is adapted to use the mode