Page 15 - Shimadzu Journal vol.3 Issue1

Environmental Analysis

Hydraulic Fracturing and the Environment

William Lipps, PhD, Shimadzu Scientific Instrument Inc.
1. Introduction Sand is defined as a particle size distribution ranging from 60 to about
2000 microns. The best “sands” for use in hydraulic fracturing are
Hydraulic fracturing is a well stimulation process used to improve
perfectly spherical ceramics with a very narrow grain size distribution
recovery and production of oil and natural gas from unconventional
to maximize porosity. The selection of material and grain size plays a
petroleum deposits. Coal bed methane and gas shale are examples of
key role in hydraulic fracturing. Instruments, such as the Shimadzu
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unconventional petroleum deposits that require “fracking”. When
SALD-2300 can be used to accurately and precisely measure grain size
fracking a well, a large volume of water mixed with sand and chemicals
distribution between 0.017 and 2000 microns in samples from very
are injected into the formation at pressures high enough to cause the
low to high concentrations of suspended particles.
rock to crack. The sand fills the fissures creating channels that allow the
gas to escape into the pipe. Coal bed methane gas deposits do not Surfactants
require as much water as shale gas deposits. Because shale “fracking” Surfactants are used as a wetting agent that, when used along with other
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requires millions of gallons of water, there is genuine concern that the chemicals, can significantly increase to productivity of a well. Unlike
environment will be adversely impacted. many other techniques used to monitor surfactants, the Shimadzu
LCMS-8040 can be used to simultaneously analyze anionic, amphoteric,
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Fig. 1 illustrates the five stages of a fracking operation . These are: 4
1) Acquire enough water needed for the hydraulic fracturing of the and non-ionic surfactants in very complex environmental samples. 5
well. This could be up to 5,000,000 gallons of water. Simpler and less expensive methods, such as Standard Methods 5540
2) Mix the chemicals with the water. determine surfactants as “groups” that can be extracted and measured
3) Inject the water plus chemicals into the well. using a spectrophotometer such as the Shimadzu UV-1800.
4) Recover the flow-back water and production water (hydraulic
fracturing wastewater) 3. KCL, Guar, and Cross-linkers
5) Treat and dispose of the wastewater
Step 1 notes that the fracking operation needs to acquire millions Cross linkers are usually boron or zirconium compounds that are
of gallons of water. This water may be withdrawn from relatively used to “link” guar gum molecules together. The guar is a water
clean fresh groundwater or surface water supplies and soluble polymer used to thicken the fracking fluid and hold the
contaminated with fracking chemicals and salts dissolved from the sand in suspension as it is carried through the pipe and into the
formation. Some petroleum companies are starting to recycle fractures made in the shale. Addition of potassium prevents
flow-back water, but most of them still dispose of it by deep well negatively charged carboxymethyl groups on the polymer from
injection. repelling each other allowing the polymer to occupy less space
Mixing the chemicals with fresh water could result in spills at the than it would if potassium had not been added. Potassium or
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mixing site. If mixing zones are not lined or contained there is the Sodium Chloride is also added to the fracking solution to
possibility of ground and surface water contamination from a spill.
prevent, or minimize, swelling of clay minerals. Boron, sodium,
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and potassium along with other trace metals, such as iron,
2. The major components in “fracturing” fluids and how calcium, and magnesium, are readily determined by Inductively
to analyze for them
Coupled Argon Plasma Atomic Emission Spectroscopy
Sand (ICAP-AES) methods, such as USEPA Method 200.7 . Because the
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Sand is used to keep the fractures open so that gas can flow through. drilling solutions are prepared containing very high salt content,

Fig. 1 Five Stages of a fracking operation

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