Stiffness tuning and dynamic force balancing rotors of downhole drilling motors

Abstract

A method of manufacturing a power unit for a downhole drilling motor includes fabricating a stator that provides two or more stator lobes that define an internal profile, and fabricating a rotor that provides at least one rotor lobe that defines an external profile that both rotates and precesses within the internal profile during operation. At least one of an external geometry and an internal geometry of the rotor along all or a portion of the rotor may be varied to alter a stiffness and mass of the rotor and thereby optimize stiffness and force balancing with respect to the stator. The rotor may then be rotatably positioned within the stator and thereby optimize the functioning and reliability of the motor power unit, of the downhole drilling motor assembly, of associated downhole drilling equipment, and to enhance directional drilling tendency modelling and directional drilling trajectory control.

Dependencies are inferred from the claim text.