American Oil and Gas Reporter - September 2018 - 77

SpecialReport: Tubulars Technology
High reservoir temperatures previously
hindered expandable refrac liners' growth,
reports Enventure Engineering Manager
Nanda Boddeda. "After the liner is installed
and expanded, it cools rapidly when
pumping begins. In high temperature
reservoirs, the rapid cool-down creates
forces in the steel that can strain the connections enough for them to leak or even
part," he warns.
"In response, we have developed two
connections for solid expandable refrac
liners that are strong enough to withstand
extreme temperature differences (delta-Ts)
between the surface/frac fluid and bottomhole temperatures," Boddeda reports. "Our
new standard connection can handle deltaT's up to 200 degrees F, enough for areas
such as the Permian Basin. An even tougher
design can endure delta-T's as high as 300
degrees, allowing expandable liners to be
used in hotter reservoirs such as the Eagle
Ford and Haynesville."
For offshore and international applications, Enventure has developed expandable systems that eliminate all loss in
inner diameter, Meiners reports. Like Enventure's other expandable tubulars, these
monodiameter systems expand the tubular
by using hydraulic pressure to push a
cone through it. To achieve monodiameter,
Meiners says the cone is opened downhole and closed once its job is done, allowing the system to expand to the same
diameter as the hole or casing above.
"This technology allows operators to
put low- or high-pressure zones behind
pipe without sacrificing diameter," Meiners says. "This opens up more opportunities in well construction and production,
such as multiple isolations in the same
well with same ID, or enabling enhanced
oil recovery for long step-out target
reservoirs."
Improved Bearings
As lateral lengths trend upward, so
have the loads placed on surface equipment
such as top drives, mud pumps and frac
pumps, observes Jesse Yorty, principal
application engineer at The Timken Company. Noting that unplanned downtime

Long laterals place greater loads on the bearings inside top drives, mud pumps and hydraulic fracturing pumps. Bearing provider The Timken Company says it can ensure bearing lives meet customer expectations by leveraging application-speciﬁc engineering
alongside advances in bearing design and enhanced surface technologies.

often carries a significant cost, he encourages equipment manufacturers to
make sure their new designs use bearings
capable of withstanding those loads.
Working with a bearing manufacturer
rather than relying solely on catalog
ratings can ease bearing selection, Yorty
suggests. "How bearings are installed,
the type of lubrication used, and the operating temperatures can cause actual
bearing life to vary significantly from
catalog life calculations, which are based
on reference conditions," he explains.
"Reputable suppliers can evaluate all environmental factors and recommend or
develop solutions that will enable the
bearings to meet life expectations."
By taking advantage of improvements
in manufacturing processes, surface technologies and bearing design, Yorty says
it often is possible for an equipment manufacturer to increase loads without substantially increasing the bearing's size.
This eliminates the cost and time associated with redesigning the equipment to
accommodate larger bearings.
"The key is to make sure improvements
address the application's life limiting factors," Yorty emphasizes. "For example, in
a low-speed application, the bearing might
have a thin lubrication film that causes
bearing life to be limited by surface

initiated damage or wear. If equipment
designers assume material is the limiting
factor, they may pay two or three times
as much for a special material but not see
any change in bearing life. In this scenario,
they should look at enhanced surface technologies that compensate for the thin film
and increase wear resistance.
"In other cases, debris can limit bearings to a fraction of their expected life,"
Yorty continues. "By specifying a bearing
that can withstand debris, equipment
manufacturers and end-users can achieve
significant increases in run time."
To identify an application's potential
life limiters, Yorty says bearing manufacturers combine experience with advanced simulation tools. "It takes time to
analyze an application, but by doing so,
we can suggest enhancements that will
ensure bearing life meets or exceeds expectations," he concludes.
r

Coming In October
Oil Field Chemistry and the Eagle
Ford, plus distribution at the PBPA
(Permian), OIPA (Oklahoma),
COGA (Colorado) and IPAA (USA)
conventions.
SEPTEMBER 2018 77

American Oil and Gas Reporter - September 2018

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