I N NOVATI N G WH I LE DR I LLI N G
Drill pipes, BHAs evolve
as wellbore geometries
push existing boundaries
Industry steps up downhole performance by giving connections
greater fatigue resistance and enhancing BHA steering capabilities
BY STEPHEN FORRESTER, CONTRIBUTOR
E xtended well lengths, deeper well depths and more com-
plex wellbore geometry are leading to the need for higher-
performance drill pipe and BHAs. Technology providers
are focusing on improving durability and decreasing cost of
ownership, through things like better fatigue resistance, the use
of steel with a higher alloying content, and integration with drill-
ing software.

Connection technology for drill pipe, BHAs
In the drill pipe market, innovation cycles do not occur with
nearly the same frequency as that of downhole technologies or
rig equipment, explained Guillaume Plessis, Senior Director of
Highlights
Innovations around connections focus
on greater fatigue resistance, increased
makeup torque and faster makeup speed.

Proprietary connections gain market
share amid increasing use of advanced
BHAs, such as automated RSS for precise
directional control.

More accessories are being added to BHAs
to remove friction, dampen vibration and
reduce stick-slip, while better integration of
simulation with rig systems are allowing for
automated, optimized steering decisions.

22 Technical Support Services for NOV’s Grant Prideco business
unit. So the company’s emphasis remains on its Delta drill pipe
connection, which Mr Plessis said was designed to provide per-
formance and lower total cost of ownership and has continually
delivered on these two fronts over the past six years. Delta 544,
for example, offers the option of using a larger 5 ½-in. pipe with a
small tool joint outer diameter — comparable to that of 5-in. drill
pipe — which allows drillers to drill an 8 ½-in. hole with a larger,
stiffer pipe. This can lead to increased ROP.

The company has also worked on giving the connection greater
fatigue resistance, which eliminates the need for cold-rolling of
drill pipe connections, as well as the capability to use an extended
makeup torque — an increase of 17%. Compared with NOV’s pre-
vious XT connection, Delta also has a 50% faster makeup speed,
yielding up to 4 seconds saved per connection makeup and
breakout. NOV is also working on the development of two other connec-
tions. The first is a connection for bottomhole assemblies (BHAs),
currently branded as AILM. “The objective is a bit different for this
technology, as we want to optimize fatigue resistance,” Mr Plessis
said. “The challenge with a BHA connection is that the tools are
very stiff, and most bending occurs at the level of the connection,
requiring innovative solutions to cope with fatigue.”
The second technology is a smaller connection being run on
a limited basis in niche applications. “The Nano connection is
being run on a different type of strings used for clean-out or work-
over operations, or in through-tubing drilling,” Mr Plessis noted.

“These are very specialized operations, and we’re typically com-
peting with premium tubing connections in this category. While
ruggedness could be a benefit of implementing Nano, the cost is
typically higher, and our customers do a very close evaluation
M A R C H/A P R I L 2023 • D R I L L I N G C O N T R AC T O R