Patent ID: 7191852
Filing Date: 2007-03-20
Classification: E21B

Abstract:
1. An apparatus for imparting mechanical vibration on a down-hole drilling system, comprising: a body having ports configured to pass fluid through the body; first and second couplers configured to couple the body to the down-hole drilling system; and a rotating member located at least partially in the body and rotatable about an axis of rotation in response to flow of the fluid, wherein rotation of the rotating member generates mechanical vibration imparted on the down-hole drilling system, wherein an interior surface of the body comprises a first lobed geometry having a first number of lobes and wherein an exterior surface of the rotating member comprises a second lobed geometry having a second number of lobes, the second number of lobes being different than the first number of lobes, wherein a center of gravity of the rotating member is offset from the axis of rotation.