Geoscience Reference
In-Depth Information
CO
2
underground near residences and communities. There is at least one
example of public opposition to CO
2
injection leading to cancellation of a
project in Europe.
25
The Sleipner Project
The Sleipner Project in the North Sea is the first commercial-scale
operation for sequestering CO
2
in a deep saline reservoir. The Sleipner project
has been operating since 1996, and it injects and stores approximately 2,800
tCO
2
per day, or about 1 MtCO
2
per year.
26
Carbon dioxide is separated from
natural gas production at the nearby Sleipner West Gas Field, compressed, and
then injected 800 meters below the seabed of the North Sea into the Utsira
formation, a sandstone reservoir 200-250 meters (650-820 feet) thick
containing saline fluids. Monitoring has indicated the CO
2
has not leaked from
the saline reservoir, and computer simulations suggest that the CO
2
will
eventually dissolve into the saline water, reducing the potential for leakage in
the future.
Another CO
2
sequestration project, similar to Sleipner, began in the
Barents Sea in April 2008 (the Snohvit Project),
27
and is injecting
approximately 2,000 tCO
2
per day below the seafloor. A larger project is being
planned in western Australia (the Gorgon Project)
28
that would inject 9,000
tCO
2
per day when at full capacity. Similar to the Sleipner and Snohvit
operations, the Gorgon plans to strip CO
2
from produced natural gas and inject
it into deep saline formations for permanent storage.
Unmineable Coal Seams
U.S. coal resources not mineable with current technology are those where
the coal beds
29
are not thick enough, or are too deep, or whose structural
integrity is inadequate for mining. Even if they cannot be mined, coal beds are
commonly permeable and can trap gases, such as methane, which can be
extracted (a resource known as coal-bed methane, or CBM). Methane and
other gases are physically bound (adsorbed) to the coal. Studies indicate that
CO
2
binds even more tightly to coal than methane.
30
Carbon dioxide injected
into permeable coal seams could displace methane, which could be recovered
by wells and brought to the surface, providing a source of revenue to offset the
costs of CO
2
injection.
