Patent ID: 6527069
Filing Date: 2003-03-04
Classification: E21B

Abstract:
for drilling a subterranean formation, comprising:a substrate having a longitudinal centerline, a radially outermost side wall, a substantially circular end face, and a substantially circular bottom face, the end face comprising, as taken in radial cross-section longitudinally parallel to the longitudinal centerline: a preselected topographic configuration including a first annular arcuate surface exhibiting a convex shape defined by a spherical surface of revolution having a center point coincident to the longitudinal centerline; a second annular arcuate surface exhibiting a concave partial surface of a first toroid having a center point radially offset from the longitudinal centerline; a third annular arcuate surface exhibiting a convex partial surface of a second toroid having a center point radially offset from the longitudinal centerline; an annular radially inset side wall surface extending generally vertically downward from the third annular arcuate surface; an annular ledge surface extending generally perpendicular to the longitudinal centerline, and extending radially outwardly from the annular radially inset side wall surface to the radially outermost sidewall; and at least one first recessed region extending generally transversely to the longitudinal centerline; and a volume of superabrasive material disposed over the end face, the volume of superabrasive material comprising a cutting face longitudinally spaced from the substrate end face and the cutting face having a peripheral edge.