American Oil and Gas Reporter - June 2023 - 92

SpecialReport: Artificial Lift Technology
vane's placement and shape, " Fernandez
describes. " This shrinks the pressure
drop between stages, which keeps gas
in the fluid and allows each stage to lift
more fluid. "
" The improvement in gas handling can
be significant, " Rumbaugh says. " In fact,
one of our pumps has centrifugal stages
that can handle up to 52% free gas. "
The new design's extra lift means the
pump needs fewer stages, Fernandez reports.
As a rule of thumb, he says it only
takes three to handle the work traditionally
done by four. " That makes the ESP
shorter, which could let the operator land
the pump in the tangent section, where it
is closer to the production, " he says.
Rumbaugh adds that in some applications,
the lower stage count can reduce
horsepower requirements and power consumption.
He mentions that ESPs can introduce
harmonics into the power grid
that reduce its capacity, overheat equipment
and create other headaches for utility companies.
If harmonics get too extreme, utilities
can issue fines or cut off power.
" We have developed a harmonic halter
to purify the power the variable frequency
drive sends back into the grid. It works so
well that the power meets the Institute of
Electric and Electronics Engineers' harmonics
standard, IEEE 519, " he says.
" We designed it for unconventional plays,
so unlike traditional harmonic systems,
which work best at particular loads, the
halter stays effective even when loads fall
to 15%. This lets the operator manage
harmonics as production declines without
changing equipment. "
Electricity-Free Automation
Optimizing rod pumps using a pumpoff
controller and a VFD has proven time
and again to increase production, extend
rod life and reduce workover costs, observes
Gord Abram, co-founder of Variable
Speed Hydraulics Inc. Because VFDs require
electricity, he continues, these benefits
have been available only at sites
with access to electricity from the grid
or enough power consumption to justify
running a generator.
Through a happy accident, Abram says
he and VSH co-founder Everett Haarstad
developed a hydraulic variable speed drive
that could bring pump-off controllers to
all sites. After years of working as a
pumper and production foreman, Abram
was searching for a more reliable belt
guard when Haarstad, a farmer with extensive
experience with hydraulic equipment,
suggested replacing the belt with a
hydraulically-powered chain.
" We never managed to make the
chain work, but we realized that in the
process of trying, we had created a variable
speed drive for natural gas engines, "
Abram recounts. " That is so much bigger,
because it means pump-off controllers
can manage the pump even in areas
with no electricity. All they need is an
engine and field gas. "
In most applications, Abram says there
is excess gas in the annulus that can be
optimized with a casing gas compressor.
" As the compressor runs, it relieves pressure
on the formation, allowing more
emulsions to flow into the pump, " he
points out. " That will cause the pumpoff
controller to accelerate the jack and
bring more production to surface. "
By itself, a casing gas compressor
has the potential to increase production
up to 60%, Abram reports. Enabling
pump-off control will not affect production
as dramatically, but reducing
fluid pound and other wear and tear on
equipment can deliver substantial savings.
Add those benefits together, and the system
generally will pay for itself in less
than a year, he estimates.
Abram emphasizes that the hydraulic
With a hydraulic variable speed drive, operators can use pump-off controllers on sites
that lack the electricity required to power a variable frequency drive. Variable Speed Hydraulics
says the production gains and cost savings from the pump-off controller can
be augmented by using the same drive to run a casing gas compressor.
92 THE AMERICAN OIL & GAS REPORTER
drive differs from past attempts to run
pumpjacks with hydraulics. " Most of
those involved replacing a traditional
pumpjack with a hydraulic system that
could lift the rod out of the well, which
can require 15,000 or 20,000 pounds of
pressure and a huge oil reservoir, " he
says. " To turn an existing pumpjack, we
only need 1,800-2,500 psi. "
According to Abram, that approach
translates into safe and reliable operations.
" The system comes with a small maintenance
manual, but other than changing
the hydraulic filter and lubricating oil
after the initial break-in, little needs to
be done. The tank that holds the oil is
sealed, so it should be able to circulate
forever without contamination. "
In recent field testing, the system ran
for 625 days without any issues, he
reports. So far, 12 systems have been deployed
in Canada and Texas. " We have
had the odd oil-cooling fan failure, but
that is an easy fix. All the operator needs
to do is pop a clip out to remove the old
fan and plug the new one in, " he says.
For wells with easy access to power,
Abram recommends using a VFD because
electric motors require less maintenance
than natural gas engines. However, the
hydraulic drive excels in locations where
running power is impossible or impractical,
he advises. " Bringing out a natural gas
engine and our hydraulic drive is much
more convenient and environmentally
friendly than negotiating with landowners
and clear-cutting brush to run power
polls, " he comments.
" Not every well needs a VSH system,
but every producer has at least one remote
or otherwise inaccessible well in their

American Oil and Gas Reporter - June 2023

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