Abstract: Roller cone drill bits are provided with cutting elements and cutting structures optimized for efficient drilling of soft and medium formations interspersed with hard stringers. The cutting elements and cutting structures may be satisfactorily used to drill downhole formations with varying amounts of hardness. The cutting elements and cutting structures may also be optimized to reduce tracking and increase wear resistance.

Abstract: Roller cone drill bits are provided with cutting elements and cutting structures optimized for efficient drilling of soft and medium formations interspersed with hard stringers. The cutting elements and cutting structures may be satisfactorily used to drill downhole formations with varying amounts of hardness. The cutting elements and cutting structures may also be optimized to reduce tracking and increase wear resistance.

Abstract: The present application describes bit design methods (and corresponding bits, drilling methods, and systems) in which the three-dimensional trajectory of an individual tooth cutting into the formation can be obtained and visualized from computer drilling simulator. In order to improve the drilling efficiency of each tooth, it is necessary to orient the tooth three-dimensionally in such a way that its longer crest is perpendicular to the scraping direction, and the top part of the tooth is angled to follow the indentation direction. Such a three-dimensional orientation allows the stress across the surface of the tooth to be more uniformly distributed, thereby, reducing breakage of the tooth.