American Oil and Gas Reporter - October 2019 - 88

SpecialReport: Oil Field Chemistry
centric blends had an average cumulative
three-month production of 7,464 boe for
every 1,000 feet of lateral, while the
others produced 6,679 boe for every 1,000
feet of lateral despite using 50 pounds
more proppant per foot, according to data
from RS Energy."
Hill says the difference in production
between the wells has persisted for three
years (Figure 1). "The reservoir centric
chemistry offsets the decline curve, providing incremental barrels," he assesses.
Growing Integration
Operators are taking a more integrated
approach to chemistry, Hill remarks. "In
the past, completion engineers would be
the primary people asking about completion chemistry," he recounts. "Today,
interest has spread upstream to the geology
and geophysics folks who describe the
reservoir and make predictions about how
it will produce."
By incorporating completion chemistry
into their models, these geoscientists can
more accurately predict wells' production,
costs and returns, Hill explains.
As operators in many plays shift focus
to infill drilling, they must grapple with
fracture-driven interactions between wells,
Silas notes. While completing a child, or
infill, well occasionally boosts the parent's
production, the effects frequently are
detrimental. For example, the child well's
completion could alter pressure gradients
and flood the parent.
"The industry is using several approaches to mitigate frac-driven interactions," Silas says. "These include increas-

ing well spacing or using smaller treatments on the infill wells to minimize the
chance of cross-well communication;
shutting in, pre-loading, or conducting a
preventative refrac on the primary well
to protect it; and adopting modified zipper
fracs or cube development techniques to
minimize the time between completions."
The right chemistry can complement
those approaches, Silas says. "In many
applications, the chemistry's goal is to
improve the mobility of the infill well's
completion fluid and the in situ water and
oil," he outlines. "This reduces the chance
of a phase blockage or shortens its duration
while improving oil recovery."
To illustrate how much chemistry can
help, Silas describes a remediation treatment for a well targeting the Woodford
Shale in Grady County, Ok. "The primary
well had been on production for 250
days before an infill well's completion
severely reduced its production," Silas
recalls. "Even 100 days after the completion, production had not returned to
previous levels. To restore it, we designed
a remediation program to mobilize the
trapped water and remove the phase
blockages it created.
"After the program, the primary well's
water production spiked. Once the water
was unloaded, oil production returned to
prior levels," Silas reports. He estimates
the program accelerated the well's recovery
by 200 days.
Water Recycling
"Water is a precious resource for
both the oil and gas industry and the

In December, this SpaceX Falcon 9 rocket delivered a particularly corrosive strain of microbes from the Permian Basin to the International Space Station. By studying those microbes' effects in microgravity, where biofilms grow more rapidly than they do on Earth,
Nalco Champion is deepening its understanding of localized corrosion. The company
says the research is part of a broader effort to help customers assess their microbial
risks more precisely and identify the most cost-effective solutions.

88 THE AMERICAN OIL & GAS REPORTER

communities in which it operates," notes
David Horsup, vice president of research,
development and engineering (RD&E)
for Nalco Champion's upstream business.
"It will be even more precious in the
future, so we are finding ways to help
operators recycle produced water at economically attractive costs.
"As part of that effort, we are developing friction reducers (FR) that work in
produced water with extremely high concentrations of total dissolved solids," Horsup relates. "Our newest FR polymers
hydrate/uncoil and reduce friction reliably,
even at very high TDS levels of 240,000
parts per million. This allows flowback
and produced water to be reused, minimizing dependency on freshwater."
Nalco Champion also is refining water
treatment chemistries, according to Vic
Keasler, the company's RD&E director
for oil field chemicals. He says the company has developed a comprehensive program for treating produced water that
controls iron sulfide, hydrogen sulfide
and microorganisms.
"With an effective treatment, recycling
produced water can deliver a great return
on investment," Keasler says. "An operator
we worked with in the Fayetteville Shale
went from recycling none of its produced
water to recycling all of it, which reduced
each well's freshwater consumption by
20-50 percent and saved the operator
$1.2 million in water-related costs."
Digital technologies also are beginning
to impact water treatment. Keasler points
out that with sensors replacing manual
water sampling and dosing, remote monitoring systems and algorithms can automatically determine how much chemistry
is required to treat the water effectively.
Microbial Control
Microbial risks continue to be a challenge in the oil and gas industry. When
unchecked, microbial growth can lead to
localized pitting corrosion, hydrogen sulfide production and fouling, Keasler notes.
He describes treating completion fluids
with microbial control chemistries as critical to reducing microbial risks, even in
areas where the risk appears low. "The
Eagle Ford is a classic example," he says.
"Because downhole temperatures there
often exceed 250 degrees F, many operators assumed microbial treatment would
not be required.
"Unfortunately, that proved not to be
the case," Keasler says. "While the downhole temperature limited growth, organ-

American Oil and Gas Reporter - October 2019

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