STANDARD HANDBOOK OF PETROLEUM & NATURAL GAS ...

Drilling Bits and Downhole Tools 807
CUTTER SIZE AND DENSITY
- SIZE
RQSLD!
ltghl medium heavy
e3
3-7
>'I
CUTTER DENSITY IS DETERMINED BY MANUFACTURER
Figure 4-161. Code of cutter size and placement [54]. (Courtesy Sf€.)
Cutter/Body Type
Bit Profile
Hydraulic Design
Cutter Size/Density
D-natural diamond, matrix body
2-long taper, medium cone
R-open throavopen face radial flow
5-med. cutter size, med. placement density
Figure 4-163 shows a steel body PDC bit with standard-size cutters lightly set
on a deep inner cone profile. This bit has changeable nozzles and is best
described as having a ribbed flow pattern although there are open face
characteristics near the center and bladed characteristics near the gage. The
IADC classification code in this case is S 7 4 4.
Figure 4-164 shows a steel body core bit with a long-taper, stepped profile
fitted with impregnated natural diamond blocks as the primary cutting elements.
The bit has no inner cone. Since there is no specific code for the natural
diamond/steel body combination, the letter 0 (other) is used as the cutter type/
body material code. The profile code 3 is used to describe the long outer taper
with little or no inner cone depth. The hydraulic design code 5 indicates a fixed