Abstract
Many existing rotary steerable systems rely on non-rotating, stationary pads or stabilizers to provide changes in borehole direction. An inherent weakness with this technique is that it relies on contact with the borehole wall to achieve predictable and consistent directional control. Hole washouts and borehole rugosity can negatively impact the directional performance of these systems.
A new rotary steerable system has been developed that does not depend on wall contact by non-moving parts. This new technology uses what is being termed a "point-the-bit" technique to enable precise, consistent and predictable changes in well trajectory.
This paper presents the design objectives and theory behind the "point-the-bit" system and contrasts it with existing rotary steerable systems. A case history from a successful field trial completed in Alaska is provided and includes well objectives and operational results.
