| 摘要 |
A rotary drill bit having a plurality of circumferentially spaced gage pads for drilling bore holes of a preselected trajectory, including lateral or deviated bore holes, in subterranean formations. Each gage pad is provided with, or alternatively associated with, at least one aggressive gage, or side, cutting element having a preselected relative degree of aggressiveness. Selected circumferentially spaced gage pads comprise at least one gage cutting element, or cutting region, disposed thereon and/or comprise alternative gage-cutting elements longitudinally proximate and exclusively associated with a selected gage pad. At least one such gage-cutting element provides more aggressive gage-cutting than at least one other, less aggressive gage-cutting element disposed on, or associated with, a different gage pad. Each of the more aggressive gage pads and each of the less aggressive gage pads may be positioned about the drill bit in a wide variety of circumferential patterns including, but not limited to, an every other alternating gage pad aggressivity pattern. A further optional circumferential gage pad alternation pattern includes, but is not limited to, a first plurality of gage pads having a generally similar first level of aggressiveness being placed proximate and circumferentially adjacent each other on a selected side of the drill bit, with the remaining second plurality of gage pads having a generally similar second level of aggressiveness being placed proximate and circumferentially adjacent each other on the opposite side of the drill bit. Drill bits embodying gage-cutting elements of more than two levels or degrees of aggressivity are also disclosed.
|
