Patent ID: 8127863

Claim:
A drill bit for drilling a borehole in earthen formations, the bit comprising: a bit body having a bit axis and a bit face; a plurality of primary blades, each primary blade extending radially along the bit face, each primary blade includes a cutter-supporting surface that defines a blade profile in rotated profile view extending from the bit axis to an outer radius of the bit body, wherein the cutter-supporting surfaces of the plurality of blades define a continuously contoured composite blade profile in rotated profile view that extends from the bit axis to the outer radius, the composite blade profile including a plurality of concave regions; and a plurality of cutter elements mounted to the cutter-supporting surface of each of the plurality of primary blades, wherein each cutter element on the primary blade has a forward-facing cutting face with a cutting edge adapted to penetrate and shear the earthen formation.