American Oil and Gas Reporter - November 2020 - 64

pages 60-65_Layout 1 11/12/2020 3:01 PM Page 64

SpecialReport: Marcellus/Utica Update
every phase. "
As the super lateral dataset expands
with each new well, it creates more
cross-reference points to evaluate realtime data feeds. " If, for example, realtime data shows higher rotary torque
than the prejob torque and drag modeling
predicted, we can trend back through
the dataset to see if other wells experienced similar torque responses, why,
and what was done, " Tourigny holds,
adding that the combination of real-time
and historical data for analysis before,
during and after the job is critical to
continuously improving performance,
eliminating potential problems, and ultimately, saving the operator money.
Having high-quality data also optimizes
equipment designs. Traditionally, coiled
tubing drill-outs in longer laterals required
BHA configurations with agitators (vibrators) and dump subs to increase annular
velocities for proper circulation at greater
depths, he notes. " Analyzing the dataset
indicated that agitators and dump subs
were not needed with HCUs and joined
pipe, " Tourigny states. " With data in
hand, we sat down with our tool company

partners and operators and designed simple
BHAs that reduce cost and risk on long
laterals. HCU core drilling BHAs consist
of a bit, a motor and two sets of floats.
That's it. "
Drill String Design
All eight super laterals completed so
far have used conventional composite
plugs rather than dissolvable plugs to
avoid the risk of dissolvable materials
not fully degrading and leaving well flow
obstructions in the casing, Tourigny indicates. He adds that the mill-out bit of
choice on Appalachian Basin super laterals
is a traditional three-cone rock bit, typically
a Varel SlipStreamTM hybrid roller cone
bit with steel teeth and tungsten carbide
insert gauges designed especially for the
composite, cast iron and ceramic plug
materials.
The four-post snubbing units' ability
to automatically maintain optimal WOB,
ROP and other drilling parameters extends
bit and motor performance by staying
within the " sweet spots " of their intended
designs, Tourigny says. " When we pull
the bits after reaching TD on 20,000-

HCUs are highly versatile and adaptable, capable of conducting numerous operations
under live well conditions that traditionally have required multiple service rigs and crews,
including running tubing-conveyed perforating guns. Shown here is an extended-reach
well site during completion operations, with a ProFrac spread in place on location and an
HCU rigged up over the well. Like drilling rigs and HCUs, fracturing fleets also are evolving
to meet the unique challenges of high-stage count, long-lateral Marcellus and Utica wells.

64 THE AMERICAN OIL & GAS REPORTER

foot laterals, the cones and bearings are
generally in good shape, " he reports.
" Maximizing bit and downhole motor
life are essential to drilling 100 or more
plugs in a single run. "
Drill strings are customized for each
application based on expected torque,
drag, friction, tortuosity and other downhole factors, but typically use 27â8-inch
outside diameter jointed pipe. Although
some strings have contained segments of
23â8-inch tubing in the lateral to reduce
friction, they often consist of 27â8-inch
pipe tapered by weight rather than outside
diameter, explains Tourigny.
" The string might all be 27â8 OD to
maximize annular velocity, but the bottom
portion nearest the toe might be traditional
9.7 pounds/foot, while the portion going
through the build/heel sections and through
to surface is heavier-weight drill pipe to
maximize torsional and tensile strengths, "
he details. " As the bit moves down a
20,000-foot lateral, the downhole dynamics
can start behaving very differently than
they do nearer the heel. "
Unlike with CT drill-outs, HCUs do
not require periodic sweeps to pull the
BHA partly back up the hole to flush
fluid and debris back to surface,
Tourigny adds. The HCU's 10,000 footpound rotary table can rotate the drill
string at speeds as fast as 120 rpm
under 10,000 psi of true working pressure while flowing up to six barrels of
fluid a minute to achieve adequate annular velocities to keep the lateral swept
clean all the way at TD. Drill-out fluids
are typically slickwater or filtered recycled produced water.
" We have never had to trip partially
back out of the hole to do a sweep, and
have always maintained positive forward
momentum and high ROP on all of the
super laterals, " he avers. " That eliminates
nonproductive time and allows plugs to
be drilled out at speeds averaging faster
than one per hour from plug to plug,
even in the toe. "
Versatile And Adaptable
Once the bit reaches TD, the workstring is tripped out and slick external
upset end production tubing can be run

American Oil and Gas Reporter - November 2020

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