US Patent 7251590 Dynamic vibrational control

A method for reducing vibration of a drilling tool assembly is disclosed. The method includes modeling the drilling tool assembly based on input parameters, simulating a vibration of a drill string coupled with a vibration of a drill bit, determining an initial total vibration from output parameters generated by the simulation, determining a location for at least one vibrational control device based on the initial total vibration to reduce the initial total vibration, and disposing the at least one vibrational control device on the drill string at the determined location.