NATURAL
GAS: Tiny particles
enlisted to tackle fracking's mysteries (Friday, March 15, 2013)
Peter Behr, E&E
reporter
Can magnetic nanoparticles
injected deep underground with hydraulic fracturing liquids reveal detailed
dimensions of shale rock fractures and track movements of gas molecules?
Can other particles -- that
change form when they encounter oil -- be "interrogated" for clues
about the amounts of oil in dense shale formations?
These are among the goals of
the Advanced Energy Consortium (AEC), headquartered at the Bureau of Economic
Geology at the University of Texas, Austin. It brings together university
researchers and industry scientists seeking scientific breakthroughs that
would remove some of the mystery in unconventional gas and oil development
miles below ground. The 4-year-old venture has spent about $40 million so
far.
Natural gas prices are still
below most drillers' break-even points, analysts say. Wide disparities exist
in best- and worst-case estimates of recoverable shale gas and oil resources.
So the use of nanotechnology to boost efficiency and production has a
substantial payoff potential, says consortium project manager Mohsen
Ahmadian.
 |
Researchers
at the Advanced Energy Consortium, part of the University of Texas' Bureau
of Economic Geology, inspect nanoparticles in solution. Photo by David
Stephens, courtesy of BEG. |
"Even though the industry
has gotten good at fracturing, we don't know the exact extent of the fracture
networks," Ahmadian said. That uncertainty can hamper a driller's search
for the best fracturing techniques or cloud decisions about how much
additional drilling and fracturing is necessary to exploit a shale formation.
So, in one part of the AEC
agenda, the search is on for nano "contrast agents" that will
penetrate the fractured shale rock and deliver a three-dimensional portrait
of the fracking results. Nanoparticles are generally defined as being smaller
than 0.1 micrometer in length (1 inch equals 25,400 micrometers).
"We want to have a more
intelligent understanding of our resources," Ahmadian said. "If you
have a previous understanding of how a particular reserve produces after a
fracture, but you don't know how far you've penetrated, you continue
fracking."
But with a contrast agent,
"you could get a much higher-resolution image of the fracture network
and you might say, 'This is telling me: Stop fracking, start
production,'" he said. "The answer is not always drilling more
wells. We want to give engineers better information so they can make better
decisions."
The venture has enlisted as
industry partners Schlumberger Ltd., BP America, BG Group PLC, Petrobras SA,
Total SA and Royal Dutch Shell PLC. More than two dozen universities and
close to 40 projects have been funded at this point, including research at
the University of Texas, Rice University, Harvard University and the
California Institute of Technology.
Some of the original partners
-- Baker Hughes Inc., ConocoPhillips Co., Halliburton Energy Services Inc.,
Marathon Oil Corp. and Occidental Oil and Gas -- have left the consortium.
The consortium is recruiting
new company members but is comfortable with the current pace of research and
membership level, Ahmadian said. The majority of the companies that have left
the consortium "didn't have sufficient bandwidth to remain actively engaged
with the large number of funded projects," he said.
"It's a two-way
process," he added: Mentors from the member companies work with the
funded university researchers and help set directions for research. "The
[university] nanotechnology experts help the members understand their
technology," Ahmadian said. "We meet somewhere in between."
An MRI for shale plays
The search for contrast agents
is not unlike the technology used in magnetic resonance imaging (MRI) exams
to reveal a heart patient's blocked blood vessels, Ahmadian said. "In an
MRI, typically, there is a contrast agent, which can be particles nano in size
that can be energized using magnetic fields, providing a contrast between
hard and soft tissues," he said.
"The human body is very
analogous to a reservoir," Ahmadian added, citing the network of
arteries and veins that connect diverse human tissues and the complex
openings fractures create in varying shale rock geology. But the analogy has
its limits, he and his colleagues acknowledge.
"The human body is very
easy," adds Scott Tinker, director of the Bureau of Economic Geology at
the Austin campus, who launched the consortium. "It's at surface
pressure, surface temperature. You can cut it open and see where the things
went. The earth has high pressure, high temperatures, nasty chemicals and you
can't really get down there. It's a tough challenge. Within a decade or less,
we might see some smart fracks, and certainly in the nearer term, things
could be put into the fracking fluids to enhance remote sensing
capabilities."
"The pharmaceutical
industry has been able to produce materials safe enough to be injected into
humans, that are degradable and so can be disposed of safely," Ahmadian
said. "We want to use them in an analogous situation" in shale
plays. "There is a lot of promise there."
Another research project
involves novel "nanoreporter" compounds that release signaling
molecules when they encounter oil, he said. These markers can be recovered
after they travel through the reservoir and are brought to the surface, and
their concentrations would give drillers an idea of how much oil remains in
the reservoir.
An even more complex
application involves proppant materials that operators force underground into
the fractured spaces to keep them open so oil and gas can pass through.
Researchers are working on adding nanobubbles to proppants that could respond
to sound waves, recording changes in velocities and flows of oil or gas
traveling toward the surface.
Ideally, to take the technology
even further, there would be a communication channel between bubbles and the
operators' monitors allowing the signals to be read in real time, he said.
"That's a pretty big challenge to have enough power and communications
to accomplish that. That is something we're trying to address."
30 patents in process
The project has produced more
than 30 patents in various stages of development, Ahmadian said. The company
members have equal access to this knowledge through royalty-free,
nonexclusive licenses.
The consortium's university
partners don't necessarily know which technologies are moving toward
commercial application at the companies, he added. "The charter of the
AEC is not to make commercial solutions. We are trying to develop a number of
pre-commercial research concepts that we take to a certain level of
development and pass on to the members," he said. "The members have
the rights to all the patents, and if they choose to, they can commercialize
them. We may not know how far they have gone."
Nanotechnology is already in
use in more basic drilling applications: improving pipe coatings, for
example. The more advanced applications on the consortium's list could be in
the fields before the end of the decade, Ahmadian said. "I would venture
that five years is a pretty conservative time frame.
"The nanoscale materials,
used in day-to-day work in scientific labs, are produced in small
scale," he said. "Once we develop a technology we feel is ready, we
have to marry that to the chemical industry, to build these in large
quantities for injection into reservoirs. Before we get there, we have to
make sure the compounds we are developing can survive in the much harsher
environment or reservoirs," he added. "And we have to make sure the
outcome is environmentally safe."
The consortium has already had
meaningful results, he said, although he cannot share details of the road
map, which are proprietary to the member companies.
"We have a very complex
set of research tasks that are being worked on in parallel fashion,"
Ahmadian said. "We are very optimistic. There are a lot of challenges.
We are not unworried, but we are in the forefront of a brand-new science that
is very exciting. Even if it is successful in recovering 1 percent of the
resources remaining in place, we will have a significant economic
impact."
