Patent ID: 6164394
Filing Date: 2000-12-26
Classification: E21B

Abstract:
A drill bit having a central axis for drilling a borehole in formation material comprising:a bit body having a bit face and a plurality of blades for rotation in a predetermined direction of rotation about the bit axis;a plurality of radially-spaced cutter elements mounted in a row on a first of said blades, said cutter elements having cutting faces with cutting tips for cutting the formation material;wherein said row includes at least first, second and third cutter elements, said second cutter element being mounted between said first and third cutter elements on said first blade;wherein said cutting tips of said first and said third cutter elements are disposed at leading angular positions relative to the angular position of said cutting tip of said second cutter element; anda second plurality of radially-spaced cutters mounted on a second of said blades, said second plurality including at least one cutter element that is redundant to at least one of said first, second, and third cutter elements on said first blade.