American Oil and Gas Reporter - June 2019 - 54

SpecialReport: Water Management
swing the economic balance to more expensive systems to treat
local water to lower the overall cost. In water-scarce regions,
the social costs of diverting high-quality water sources from
more traditional uses will have a strong impact on issues such
as license to operate and public relations.
Brackish groundwater sources historically have been a good
source of completion fluids, but are now being viewed as a

potential substitute for freshwater in some water-stressed regions.
As brackish desalination capacity grows, industrial consumers
will feel pressure to reduce use of this source. I think transporting
water from the Gulf to West Texas is a nonstarter. Water flows
downhill, and most of West Texas sits above 2,500 feet elevation.
The economics of pumping or hauling seawater out west just
will not pencil out.

OPTIMIZING QUALITY

What are the major challenges for water quality management going forward? How do different sources affect

quality? What techniques are required for blending fresh and
treated water for completions using cross-linked gels as opposed
to slickwater?
PATTON: The biggest challenge will be managing the

effects of induced seismicity on disposal well capacity in the
Delaware Basin. The Delaware already produces a significant
amount of produced water and any disposal well restrictions
will strain capacity concerns that already exist. In terms of the
produced water quality, one typically sees changes in chloride
levels, iron, bacteria and sulfides from different sources. In
itself, this is not a challenge, but designing systems to account
for these changes is critical. Most systems are designed
assuming a steady state, but with produced water, a steady
state doesn't exist, so variability has to be accounted for in a
system design.
As for cross-linked gel chemistries, these gels have a
higher sensitivity to chloride levels, so special attention has
to go into maintaining a consistent blend. We patented a
process using real-time monitoring and water chemistry
testing to maintain a blend for a stable, consistent fluid. The
other challenge is that boron in produced water can cause
premature cross-linking. Borates typically are added to a
cross-linked gel system to create a delayed cross-linking,

which basically means the gel will thicken once the fluid is
moving down hole. Boron in produced water can cause this
thickening to happen immediately, making it very difficult or
even impossible to pump down hole. So part of automated
blending has to include boron testing in real time. Boron inhibitors can be added to prevent boron from causing premature
cross-linking, but one must know how much boron is present
to inhibit its effect.
Also, it is common for working tanks during a frac job to be
contaminated or source water to see bacterial growth if not
aerated. One common way to prevent this is to recirculate water
between stages of a frac to clean working tanks or prevent
bacterial growth in the source water storage system. Of course,
even better is to include aeration in the storage system.

How can produced water treatment be standardized
across an operation rather than applying a customized
approach for each site? When is customization necessary? How
can operators reduce treatment costs through greater use of
standard practices?
PATTON: Even with variability in produced water quality,
standardization is very possible and necessary. Rather than
relying on a service provider to define the produced water reuse
specification, the operator should take control over its program
and develop quality needs internally. By developing a produced

Mark Patton is president of Hydrozonix LLC. He joined the company in 2012 as an applications
engineer after serving for 14 years as vice president at American Remedial Technologies and seven
years as a program manager at Waste Management Inc. Patton holds a B.S. in chemical engineering
from the University of Southern California.

MARK PATTON
President
Hydrozonix
54 THE AMERICAN OIL & GAS REPORTER

American Oil and Gas Reporter - June 2019

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