Patent ID: 7540340
Filing Date: 2009-06-02
Classification: E21B

Abstract:
1. A drill bit, comprising: a bit body; at least one roller cone attached to the bit body and able to rotate with respect to the bit body; and a plurality of cutting elements disposed on the at least one roller cone, at least one of the plurality of cutting elements comprising: a barrel axis; a first area defining a secondary wear surface, wherein the first area is formed as a surface on a trailing edge of the at least one cutting element; a second area proximate the first area and defining a main wear surface, wherein the second area has a radius of curvature substantially equal to a radius of a borehole; a third area proximate the second area and defining a leading edge relief zone; a fourth area defining a spherical cutting surface; and a non-spherical transition zone disposed between the fourth area and the first and second areas, wherein the barrel axis intersects the transition zone.