Page 222 - Practical Well Planning and Drilling Manual

Section 2 revised 11/00/bc 1/17/01 12:04 PM Page 198

[ ] Well Programming
2.4.6

H Horizontal steering application
Y Predominantly conical tooth inserts
J Jet deflection bit
Z Other shape inserts

For instance, a security bit type ERASS84FD could be described by
IADC code 517WMBXC as a soft to medium sealed bearing insert bit
with enhanced cutters, motor application, special seals, predominantly
chisel-shaped teeth, and a center jet.
IADC fixed cutter bit classification. As with roller cone bits, IADC
have defined a classification system for describing fixed cutter type
bits. There are four digits that classify the type of body material, cutter
density, size/type, and body profile. Following is a summary of how the
system works.

First digit: body material
M for matrix or S for steel.

Second digit: cutter density
Ranges 1 to 4 for PDC bits and 6 to 8 for surface set (e.g., dia-
mond) bits. The PDC bit number relates to the cutter count; there is
a higher number for a heavier set. The surface set number relates to
diamond size.

0 Reserved for future use
1 Less than 31 x 0.5 in diameter PDC cutters
2 30 to 40 x 0.5 in diameter PDC cutters
3 40 to 50 x 0.5 in diameter PDC cutters
4 50 or more x 0.5 in diameter PDC cutters
5 Reserved for future use
6 Larger than 3 stones/carat
7 Between 7 and 3 stones/carat
8 Smaller than 7 stones/carat
9 Reserved for future use

Note: For larger or smaller diameter cutters, use the ratio of diam-
eters. So 50 x 0.25 in cutters would equal 25 x 0.5 in cutters. This does
not include extra cutters, e.g., gauge trimmers and side-cutting cutters
(sidetrack bit).

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