| 摘要 |
A shear cutter drill bit for drilling a subterranean formation is provided having a bit body; a bit face on the bit body having at least a center zone, an efficienc y zone, and an outer zone, the efficiency zone being located between the center zone and th e outer zone; and a plurality of cutters having a backrake angle located on the bit face; wherein a majority of the cutters located in the efficiency zone of the bit face hav e a more aggressive backrake angle than a majority of the cutters located in the cent er zone of the bit face and a majority of the cutter located in the outer zone of the b it face.
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