부산대학교 도서관

A rolling cone drill bit for drilling a borehole in earthen formations. In an embodiment, the bit comprises a bit body. In addition, the bit comprises a cone cutter mounted on the bit body and adapted for rotation about a cone axis in a cutting direction. Further, the bit comprises at least one transition insert mounted to the cone cutter. Still further, the bit comprises a first asymmetric insert mounted to the cone cutter. Moreover, the bit comprises a second asymmetric insert mounted to the cone cutter. Each insert includes a cutting surface with a leading side relative to the cutting direction. The leading side of the first asymmetric insert has a leading geometry and the leading side of the second asymmetric insert has a leading geometry that is different than the leading geometry of the first asymmetric insert.