| 摘要 |
A rotary drag bit (110) exhibiting enhanced cutting efficiency and extended life is provided. The rotary drag bit comprises a bit body having a face surface, and a plurality of cutters coupled to the face surface of the bit body. The plurality of cutters comprises at least one pilot cutter (162) and a rotationally trailing larger, primary cutter (164) at substantially the same radius and, optionally of slightly less exposure. The pilot cutter (162) is sized and positioned to pre- fracture the formation and perform an initial cut, while the primary cutter(164) removes weakened, remaining formation material along the same rotational path. A method to pre- fracture subterranean formations using a rotary drag bit (110) having a pilot cutter configuration is also provided.
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