DRILL BIT WITH ENHANCED HYDRAULICS AND EROSION-SHIELDED CUTTING TEETH

摘要

Disclosed is a rolling cone drill bit with inner row cutting teeth having portions shielded with an erosion-resistant material that differs in material properties from the tooth's core portion that is more impact resistant. The tooth includes shielding on at least a portion of the upstream end and along portions of the flanking surfaces. It includes shield-free portions on the flanks between the root and the tooth crest. Most of the tooth's perimeter is made of the core material and is free of shielding. Gage row teeth may be angled and form a channel to direct drilling fluid from the gage region of the borehole to locations where the inner row teeth are generating most cuttings. Nozzles are provided with non-uniform orientations.