| 摘要 |
<p>Arrangements for the cutters or wear resistant inserts 62 on rolling cone drill bits 10 are disclosed. Each cone cutter includes a plurality of gage cutting elements mounted in a gage zone (80, also figure 3), a first plurality of bottomhole cutting elements mounted in a drive zone (81, also figure 3), and a second plurality of bottomhole cutting elements mounted in an inner zone (82, also figure 3). The ratio of the total number of bottomhole cutter elements in the inner zone on all three cones to the total number of bottomhole cutter elements in the drive zone of all three cones is less than 1 and specific to a particular IADC classification of drill bit.</p> |
