Patent ID: 7318492
Filing Date: 2008-01-15
Classification: E21B

Abstract:
1. A drill bit adapted for drilling a borehole with a steerable drilling system, the drill bit comprising a longitudinal axis, and a cutting profile comprising a leading face section blended with a curved region into a tapered gauge region having a tapered gauge profile, the tapered gauge region being tapered with respect to the longitudinal axis to at least a tilt angle determined by the steerable drilling system; wherein the cutting profile and the gauge profile lie wholly within a bit profile envelope comprising a three dimensional surface of two complimentary conical sections set at the tilt angle and separated by and blended with a rounded section which forms an outermost diameter of the bit profile envelope; the rounded section having a diameter substantially equal to a maximum allowable API diameter for the drill bit, and further having a radius of curvature substantially equal to one-half the diameter.