Wellbore drilling with a top drive device

A method for drilling a wellbore wherein use is made of a top drive device comprising:

• multiple electric top drive motors each having a rotor;
• a transmission to which said rotors of said multiple top drive motors are operatively connected;
• and
• a rotary stem or quill operatively connected to said transmission allowing said rotary stem or quill to be driven by said top drive motors in order to impart rotary torque to a drilling tubulars string connected to the rotary stem or quill of the top drive device,
• wherein each of said top drive motors has an operable clutch device configured to selectively connect and disconnect upon command the rotor relative to the transmission,
• wherein the method comprises providing a command to one of said top drive motors having a clutch so as to selectively connect and disconnect the rotor thereof relative to the transmission by operating said clutch.

A method to reduce torsional vibration in a drilling tubulars string during a wellbore drilling process, wherein use is made of a wellbore drilling installation comprising a top drive device comprising:

• multiple electric top drive motors each having a rotor, said rotor having an inertial moment;
• a transmission to which said rotors of said multiple top drive motors are operatively connected, wherein each of said top drive motors has an operable clutch device configured to selectively connect and disconnect upon command the rotor relative to the transmission;
• and
• a rotary stem or quill operatively connected to said transmission allowing said rotary stem or quill to be driven by one or more of said top drive motors,
• wherein the drilling tubulars string is connected to the rotary stem or quill of the top drive device, so that during the wellbore drilling process the rotating drilling tubular string and the one or more rotors operatively connected to said rotating drilling tubular string have a total inertial moment,
• wherein the method comprises providing a command to one of said top drive motors having a clutch device so as to selectively connect and disconnect the rotor thereof relative to the transmission by operating said clutch and thereby varying and controlling said total inertial moment as a control parameter for reduction of drill string torsional vibrations.