Adaptive control concept for hybrid PDC/roller cone bits

摘要

An earth boring drill bit comprising a bit body having a longitudinal axis along a path of the bit, a first plurality of cutters mounted to the body, and a second plurality of cutters rotatably mounted to the body, wherein a longitudinal axial relationship between the first plurality of cutters and the second plurality of cutters is adjustable. The first and/or second plurality of cutters may be mounted to the body in such a manner as to allow them to slide parallel to the longitudinal axis. The longitudinal axial relationship may be adjusted to exchange the first plurality of cutters and the secondary plurality of cutters between a primary cutting position and a secondary cutting position. The bit may include a sensor to provide an indication of a formation type being excavated by the bit and a processor to control the longitudinal axial relationship based on the indication.