U.S. Department of Energy - Energy Efficiency and Renewable Energy
Geothermal Technologies Office
AltaRock Energy Announces Successful Multiple-Zone Stimulation of Well at the Newberry Enhanced Geothermal Systems Demonstration
January 22, 2013
SEATTLE--AltaRock Energy today announced that it has created multiple stimulated zones
from a single wellbore at the Newberry Enhanced Geothermal System (EGS)
Demonstration site. Creating multiple stimulated zones from a single well will
dramatically increase the flow and energy output per well for the completed
system, which will include soon-to-be-drilled production wells. The overall
effect will be to lower the cost of geothermal energy production by as much as
50 percent. This is a major advancement for EGS and has the potential to move
geothermal energy from a niche role to a major player in AltaRock's energy
portfolio.
"Geothermal energy has the smallest environmental footprint of any renewable
power source we now have, and is the only renewable energy source that provides
24/7 baseload power," said Susan Petty, president and founder of AltaRock
Energy. "The purpose of the Newberry EGS project is to demonstrate AltaRock’s
new technology designed to lower the cost of EGS, and thus allow economic
extraction of heat from the earth in locations where high temperatures can be
reached by conventional drilling techniques."
Enhanced Geothermal Systems are geothermal reservoirs created in hot, low
permeability rock by injecting cold water at moderate pressure to enhance the
permeability of existing fractures. This means an EGS can be sited in areas
without naturally occurring hydrothermal resources with surface manifestations
such as hot springs and fumaroles. As such, an EGS could theoretically be sited
anywhere there is geothermal heat near enough to the surface to be economically
recoverable. Studies by MIT, the Department of Energy, the US Geological Survey
and Google have concluded that EGS technology would unleash at least 500
gigawatts (GW) of recoverable geothermal energy in the Western U.S. alone and
potentially over 3,000 GW across the US. EGS has the potential to provide a very
significant portion of the country’s electric power supply, which is currently
1,000 GW.
Until now, a major challenge facing EGS projects has been the cost. Since
geothermal wells can cost several million dollars to drill, increasing the
generation capacity of each well is critically important for making it more
competitive on the open market for electricity because it lowers the cost of the
produced power by reducing the number of wells that need to be drilled. Systems
with single stimulated zones simply don't yield enough power per well to make
the electricity produced cost competitive. Having the ability to create multiple
stimulated zones from a single well increases the amount of power produced by
the well, and thus decreases the overall cost of the power produced.
It's About the Diverters
Multiple-zone stimulation is made possible with AltaRock Energy's patented
Thermally Degradable Zonal Isolation Materials (TZIM), which are designed to
shift/divert stimulation from one zone to another, and then degrade into
non-toxic components such as water and CO2 when the stimulation is complete and
the well is allowed to reheat. The challenge was identifying materials that
persist during stimulation when the well is relatively cool, and then break down
quickly into non-damaging components when stimulation has been completed.
AltaRock has spent many years researching and testing their TZIM technology to
develop a suite of materials for a variety of conditions, and now has patented
the technology.
At Newberry, AltaRock used a TZIM made from a biodegradable non-toxic polymer
commonly used for other purposes that was specially prepared and ground to
particle sizes specific to the geology encountered in the hot, dry well, which
was drilled in 2008. After injected water stimulated the first zone, TZIM was
added to the water and partially plugged the first set of stimulated fractures
at the wellbore. This reduced flow into the first zone and slowed its growth.
Once flow to the first zone was reduced, pressurized water in the wellbore found
the next weak point and began the stimulation of a second fracture zone. At
Newberry, this process was repeated three times, and then the valve on top of
the well was closed and the well was allowed to heat up. The hot (400-600° F)
rock surrounding the well quickly heated the injected water, causing the TZIMs
to degrade. It is important to note that more than three stimulations can be
conducted from a single well if the conditions warrant it.
Next Steps
In the spring of 2013, AltaRock will test for permeability, flow rates, and
heat capturing properties of the created reservoirs. After that, production
wells will be drilled to intersect the reservoirs about 1,500 feet away from the
injection well. Once a connection between wells is made, the well system—one
injector and at least one producer—will be flow-tested to determine if the
system can support a commercial plant. If it is determined that a commercial
plant is feasible, a design will be developed, and construction permits will be
submitted to regulators. That will trigger the development of an Environmental
Impact Statement by the BLM and a public comment period. It is a long process,
but the potential payoff in renewable domestic energy is enormous.
The Newberry Volcano EGS Demonstration is partially supported by the
Department of Energy under Award Number DE-EE0002777, with $21.4 million in
grant funds from the Department of Energy to AltaRock Energy matched by an
additional $22.4 million from the AltaRock-Davenport partnership. The project is
also benefiting from the research efforts of faculty and students at the Oregon
State University, the University of Utah, Lawrence Berkeley National Laboratory,
Texas A&M, and Temple University.
About AltaRock Energy
AltaRock Energy (www.altarockenergy.com)
is a renewable energy development company focused on the research and
development of Engineered Geothermal Systems (EGS). AltaRock develops and
commercializes geothermal technology to produce clean, renewable power. The
company has filed patent applications for a portfolio of patents in the EGS area
and holds exclusive licenses for related intellectual property. AltaRock's
current activities include an EGS project in Oregon, an innovative exploration
project in Nevada as well as development of approximately 50,000 acres of land
in Washington and Oregon for Weyerhaeuser. Headquartered in Seattle, Wash.,
AltaRock was founded by Susan Petty, who is also President/Chief Technology
Officer. Source: Business Wire
More Information
More information and updates about the project can be found at:
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