I N NOVATI N G WH I LE DR I LLI N G
IADC ART Committee moves
closer to launching updated
drill bit dull grading system
When completed, new system is expected to
remove human subjectivity in grading process,
support root cause analyses of bit damage
BY STEPHEN WHITFIELD, ASSOCIATE EDITOR
In 2021, the IADC Advanced Rig Technology
(ART) Committee launched a project to
upgrade IADC’s long-standing bit dull
grading system. The objective was to
develop a more modern system for under-
standing and grading bit wear that better
supports workflows for root cause analy-
sis and continuous improvement.

“The existing bit dull grading classifica-
tion system needed to get a major upgrade,”
said Robert van Kuilenburg, Mechanical
Engineering Manager at Noble Corp and
former ART Committee Chair. “It was
heavily focused on the justification of pull-
ing and not on the root causes. It relies too
heavily on expertise, and there’s no frame-
work for metadata inclusion and limited
support for automated drilling systems. It
just doesn’t cut it in today’s environment.”
The ART workgroup, led by Mr van
Kuilenburg along with ExxonMobil’s Paul
Pastusek, Shell’s Dustin Daechsel, and
Data Gumbo’s Robin Macmillan, formed
four smaller teams to examine differ-
ent aspects of the upgrade process: drill
bit code definitions; BHAs and motors
code definitions; data management; and
case studies. During a live Virtual Panel
Discussion hosed by Drilling Contractor
on 9 February, representatives from each
team discussed the work they have done,
their planned output, work items left to
be resolved, and the estimated timeline to
completing the system upgrade.

Drill Bit Code Definitions
This team set out on its task by recog-
nizing that the current codes haven’t been
updated since 1987. Not only do they not
provide enough granularity on the types of
damage experienced so that detailed root
20 causes analyses could be conducted, but
they also require human expertise and are
subject to interpretation.

So the team set out to develop a qualita-
tive classification scheme of PDC cutters,
drill bits and tools with cutting elements,
along with second priority on quantitative
analysis. While the system will focus on
PDC bits due to their market domination,
the system will also be compatible with
other bit types. Further, it recognizes dif-
ferent levels of dull grading.

“We’re looking to split the grade in terms
of a rig grade, which is still similar to what
we do today in terms of grading at the rig,
and then we’re going to have the more
accurate forensic shop grade,” said Tom
Roberts, Vice President – PDC Strategy and
Development, NOV. “The importance of the
two is that the rig grade provides real-time
decision making and is still extremely
important, but both will come together in
terms of advanced forensics.”
New damage categories, such as cham-
fer damage and axial break, were also
added, along with a category of classes
specifically designed to evaluate the wear
on the substrates of PDC cutters. This was
a critical addition because substrate dam-
age can often indicate more substantial
damage within the BHA, said Dustin Lyles,
VP of Technology at Taurex Bits.

“When you look at, say, a corroded sub-
strate and you see a lot of pitting, you
know that’s a sign of either H2S or poten-
tially caustic mud,” Mr Lyles said. “When
that occurs on a drill bit, it’s obviously very
critical for not just the drill bit providers
but also the operators to know that there’s
H2S present or that the mud is caustic.

That lends itself into pushing that person
or that organization into looking at other
BHA components, because it’s likely that
it’s not only the drill bit that’s experienced
that type of corrosive damage.”
The group also oversaw an expansion
of the bit zone categories, from just “inner”
and “outer” to include the cone, the nose,
the gauge and the shoulder.

“The historic ‘inner two-thirds to outer
two-thirds’ system was very applicable to
roller cones, but it was not very applicable
to PDC bits,” Mr Lyles said. “We believe this
type of improved granularity into the drill
bit zones will give additional color and help
drive the root cause forensic analysis.”
The next steps for the drill bits group are
to finalize a training document with exam-
ples of the new wear categories. Later this
year, the group also expects to conduct field
trials, where companies will grade cutters
and provide feedback on the effectiveness
of the new categories. Further, this group
will work with the data management team
to develop a digital interface of the new cat-
egories for the IADC Daily Drilling Report.

BHA & Motors Code
Definitions This group is focused on the classifica-
tion of the BHA, motors, RSS tools, stabiliz-
ers and other BHA elements and has been
working to create a forensics evaluation
workflow and best practices document for
BHA coding.

“The bit dull grading system has served
very well in creating a picture of the con-
dition of the bit once it’s above rotary, and
it has been a proven tool in improving
performance. But there’s nothing that’s
been done on the BHA side,” said Paul
Neil, Senior Director of Drilling Solutions,
Engineering and Reliability at NOV.

The BHA team is comprised of five
targeted sub-groups, each tasked with
developing a coding system specific to its
area of focus: motors, rotary steerable, data
acquisition, performance enhancement
and iron (stabs, collars, subs).

The BHA coding is structured into three
levels, where the first is a high-level exam-
ination of the BHA. At this level, users can
quickly flag any issues with a part of the
BHA that require review and investiga-
tion. This coding system lists six main
codes indicating different types of damage
or reasons for failure (no damage, back-
M A R C H/A P R I L 202 2 • D R I L L I N G C O N T R AC T O R