Over time there has developed a perception that PDC bits are not typically run at high speeds. This perception has propagated from the perception belief that PDC cutters at high speeds will generate enough heat to thermally degrade the cutter or the impact damage at high speeds will destroy the cutter. However, twenty years ago when PDC bits were in their infancy, they were in fact run very successfully at high speeds. Many ROP records in these older fields were drilled with PDC bits on high speed drives. Over time however, PDC bit designs have transgressed to enable better performance when coupled with slower drive mechanisms, such as rotary and positive displacement motors (PDM).

PDC technology has evolved dramatically over the last decade and it has become evident that further substantial developments based on the type of drive mechanism being used will lead to specific designs. This is vital, as different drive mechanisms behave differently, not only with regard to RPM, but also concerning tool plus bit generated vibration, depth of cut (DOC), blade count, cutter density, profile, etc. Analyzing the history of PDC bits run at high speeds and more recently the current designs which are primarily run at lower speeds proves this hypothesis.

The developmental process for further enhancements to PDC bit performance will be two fold. One, to make the PDC bit durable enough to last over long drilling intervals without sacrificing ROP, and two, to base the design on the specific run parameters a particular drive mechanism delivers. Discussions in this paper will detail the history of PDC bits run at high speeds, while addressing the particular design and characteristics required for successfully running PDC bits at high speeds, and finally addressing the research and development currently underway to optimize high speed PDC bit performance.

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