| 摘要 |
<p>A drill bit (10), for example of a fixed cutter type, comprises at least one structure, for example a blade, having first and second rows of cutters (35a-h) thereon. The first row is configured to achieve suitable performance when the drill bit drills in concentric mode. The second row of cutters is configured to improve the performance of the first row of cutters when the drill bit drills in eccentric mode. For example, the second row increases depth of cut and wear resistance in eccentric mode drilling. The drill bit may be mounted on a bent motor (120) used in directional drilling.</p> |
