Patent ID: 8312942
Filing Date: 2012-11-20
Classification: E21B

Abstract:
1. A roller cone drill bit operable to form a wellbore comprising: a bit body having an upper direction, wherein the upper direction is the direction towards a drill string, and the bit body having an upper end operable for connection to the drill string; at least one support arm extending from the bit body; each support arm having a leading edge and a trailing edge; a lubricant reservoir disposed within each support arm; a respective shirttail portion formed as part of an exterior surface of each support arm; a respective roller cone assembly rotatably mounted on an interior portion of each support arm opposite from the respective shirttail portion; a lifting surface formed on each support arm adjacent an uppermost edge of the associated exterior surface; each lifting surface extending between the leading edge and the trailing edge of the respective support arm and having an upward inclination relative to the exterior surface; an enlarged surface formed adjacent the leading edge and the lifting surface, the enlarged surface having a sloped configuration to assist in directing drilling fluid and formation cuttings over the lifting surface; and the lifting surfaces cooperating with each other to direct drilling fluid and formation cuttings upwardly in spiraling flow paths relative to an associated drill string and wellbore.