American Oil and Gas Reporter - February 2017 - 57

SpecialReport: Shale Resource Science

Tools Boost Coiled Tubing Efficiency
By Colter Cookson
The coiled tubing industry may not
advance as quickly as superhero movie
protagonists, who often transition from
wide-eyed kids to world-saving legends
in a few hours. But thanks to clever ideas,
meticulous research and demanding applications, it is moving forward at a steady
pace.
Service company representatives say
those steps forward take a variety of
forms. For example, enterprising operators are installing sensors on their CT
strings to optimize interventions and refine completion designs. Meanwhile,
better coil manufacturing processes and
string designs are joining forces with
robust vibration tools to extend coiled
tubing's reach into progressively longer
laterals.
"Deploying coil in laterals around
10,000 feet in length has become an
everyday occurrence," says Mark Spitz,
an engineer with Cudd Energy Services.
"In response to requests from operators
wanting to drill 15,000-20,000 foot laterals,
we are looking at ways to extend lateral
reach past the 10,000 foot mark."
To meet that challenge, Spitz says
Cudd is tailoring its string designs for
long laterals. "We are manipulating the
wall thickness to ensure the coil not only
can reach its destination, but also can get
back out safely," he reports.
Spitz adds that the company is monitoring advances in tools that reduce friction
by vibrating the string. "Vibration tools
have gotten us to places we would not
have reached otherwise, and they continue
to look like a viable way to get farther,"
he comments. "We prefer tools that work
with a range of chemicals, allow beads
through, and come from a company with
a good reputation."
Spitz encourages operators to consider
how completion designs and wellbore
geometries affect coiled tubing when designing a well. He says seats, sliding
sleeves and other inner diameter restrictions can preclude the large CT strings
that offer a longer reach.
"The location of the liner top with respect to the height and the kickoff point
of the well also matters," Spitz continues.
"Consider 7-inch casing with a 41⁄2-inch
liner. If the liner top is in the curve or at
the heel of the curve, it becomes more

difficult for CT to reach the end of the
lateral because the larger internal diameter
at surface provides more space for the
tubing to buckle."
Future Directions
Spitz predicts coiled tubing's maximum
reach will continue to grow. "From the
Permian Basin to the Marcellus and Utica,
we have had operator after operator tell
us that drilling longer laterals is the most
cost-effective way to increase production,"
he reflects.
The CT industry is moving toward
more rigorous training standards, Spitz
reports. "In the past, most industry training
has been on the job, where it is prone to
human error and varying schools of
thought," he relates. "We take a professional approach to training, providing
classroom instruction to transfer procedural
and operational knowledge to our employees, as well as hands-on field training
and mentoring."
To improve efficiency, Spitz says operators often use advanced chemical mixers. "Instead of having someone pour
chemicals into a hopper, these automated
chemical plants mix chemicals precisely.
Some of these plants are equipped with

meters to analyze the fluid's composition,"
he describes. "That has led to more consistent fluid quality and a better understanding of the fluid properties' effect on
downhole conditions."
Spitz adds that Cudd is sending more
data to the customer's office during jobs.
"In addition to customary CT data such
as weight, rate, and pump and wellhead
pressures, we are able to accept data
from other vendors on location, package
it, and send it to the customer over the
cloud utilizing third-party software. The
goal is to enable better statistical analysis
to be performed post-job, and allow engineers to monitor the operation in real
time, rather than relying on verbal reports
from the field."
With commodity prices picking up,
Spitz suggests the industry's appetite for
novel CT applications will grow. "For
example, there has been a renewed interest
in ways to turn vertical wells sideways,"
he says. "We have had meetings with operators who are considering adding horizontal legs to 400-500 wells, and we discuss smaller-scale projects almost daily."
Spitz says Cudd has achieved good
results in proofs of concept for such un-

Careful planning and thorough training are key parts of Cudd Energy Services' efforts
to perform coiled tubing work in today's lengthening laterals safely and efficiently. The
company points out that its employees help develop training standards by being members of committees organized by the Intervention & Coiled Tubing Association, American
Petroleum Institute and International Association of Drilling Contractors.

FEBRUARY 2017 57

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