I N NOVATI N G WH I LE DR I LLI N G
Halliburton’s Cerebro Force in-bit
sensors, launched in 2020, cap-
ture weight, torque and bending
measurements directly at the bit,
allowing the company to map
the bit’s downhole motion .
Oculus is utilized at Halliburton’s service centers globally for
fixed cutter dull analysis. Its newest Hedron fixed cutter platform,
launched in 2022, utilizes Oculus as a key component of design for
more efficient and durable PDC bits.
In one project last year, the company worked with a direc-
tional driller in the Middle East that was looking for a bit to help
increase ROP. Halliburton, using historical data of similar forma-
tions, picked its Hedron PDC bit with Geometrix shaped cutters in
the shoulder area as a starting point. In subsequent simulations
and testing, it was found that decreasing the diamond volume
negatively affected the bit’s stability and exacerbated minor
breakage seen in the shoulder during formation transitions. This
finding led Halliburton to look for ways to alter the design pro-
file to increase cutter efficiency and minimize the potential for
instability. Based on data provided by the Oculus system, the company
kept the same profile and cutter positions as the reference bit, but
it introduced an optimum back rake scheme to increase efficiency
and lower susceptibility to impact damage. After a test run in
Halliburton’s proprietary modeling software, the cone, nose and
shoulder were examined before adjusting the back rake regime.
No changes were made in the cone area of the bit, as design
simulations performed in its bit design software indicated that
such changes might lead to over-engagement of the cone cutters,
which could lead to aggravated vibration levels and increase the
potential for downhole dysfunction.
A final test run in the modeling software saw a 26% increase in
bit efficiency compared with the reference bit. Then, a field test of
the updated bit set a field record for ROP – 81.2 ft/hr, nearly 12 ft/
hr higher than the previous record of 69.6 ft/hr.
“Oculus has really helped us in terms of understanding – at
scale – how cutters perform in many different applications,
whether that’s abrasions, impact environments or thermal-type
environments,” Mr Sostarich said. “We’re able to make better
selections on introducing new technologies to our customers.”
Collaboration and performance
NOV uses a wealth of software programs to help operators
find the right drill bit. Terra-Scope, the company’s long-standing
downhole seismic monitoring system, analyzes rock strength
data and outputs the most likely failure mechanisms for the tar-
get formation. For example, it can determine whether the bit is
more likely to fail under stress – which would require 3D-shaped
cutters – or more likely to fail under strain – which would require
full round cutters. The company then uses its Orbits software to
run simulations showing how a given bit design might perform
with rock properties specified by the operator.
Despite the sophistication of software like Terra-Scope and
Orbits, there’s still a lot of work required from field engineers to
“sort through all the different things that can happen on a rig or
happen to a bit while drilling a well,” NOV’s Mr Jennings said,
adding that looking at all the data available and making sound
recommendations requires a lot of coordination.
This is why NOV Engineer Brice-Herve Benie said he believes
the drill bit selection process is actually all about collaboration
with the operator. Choosing a profile to run in the Orbits simulator,
D R I L L I N G C O N T R AC T O R • M A R C H/A P R I L 2023
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