Patent ID: 6092610
Filing Date: 2000-07-25
Classification: E21B

Abstract:
A method for drilling a well and simultaneously steering a drill bit with an actively controlled rotary steerable drilling system, comprising:rotating a tool collar connected to a drill string, said tool collar defining a longitudinal axis;with bit shaft positioning means, pivotally rotating a bit shaft supported within said tool collar for rotational movement about a pivot point within said tool collar and in a direction counter to rotation of said tool collar, said bit shaft being rotatably driven by said tool collar and being adapted for supporting a drill bit;transmitting steering control signals to said bit shaft positioning means causing synchronous pivotal counter-rotation of said bit shaft by said bit shaft positioning means about said pivot point with respect to rotation of said tool collar, and maintaining said longitudinal axis of said bit shaft substantially geostationary and selectively axially inclined relative to the longitudinal axis of said tool collar during rotation of said bit shaft by said tool collar; andselectively rotationally braking said bit shaft positioning means in reference to external disturbances acting to divert said drill bit from its projected course.