| 摘要 |
A rotary drag bit includes a bit body having a face and an axis, a plurality of blades extending radially and longitudinally outward from the face, and at least one split cutter set. The split cutter set includes a plurality of cutters, where at least two of the cutters are primary and 'or kerfing cutters located on different blades of the plurality of blades. The pair of primary and/or kerfing cutters of the split cutter set may be located substantially the same radial distance from a center line, or axis of rotation, of the bit and located at substantially the same longitude, or elevation, on the bit as one another, or follow substantially the same rotational or helical cutting path as each other. In addition, at least one backup cutter may be located substantially the same radial distance from a center line, or axis of rotation, of the bit and located at substantially the same longitude, or elevation, on the bit as one or both primary and/or kerfing cutters, or follow substantially the same rotational or helical path as one or both of the primary and/or kerfing cutters. The cutters of a split cutter set may be configured and oriented to provide improved bit life and reduced stress upon the cutters. Other embodiments of rotary drag bits are also provided, including methods therefor.
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