This month's word is sequestration. Meanings include seizure, seclusion, segregation
and monkhood. Perhaps the most apt meanings, given the use of the word in this
issue's feature articles, are adsorption, complexing and "withdrawn from
circulation." Other uses include quarantine and punishment, seemingly insidious
allusions to the Faustian use of fossil fuels in the first place. Better late
than never, this issue focuses on the potential of geologic sequestration of the
greenhouse-forcing gas carbon dioxide, which we have for centuries produced by
burning of fossil fuels.
In our first feature, S. Julio Friedmann identifies the most promising types of
geologic sites for carbon dioxide sequestration as oil and gas fields, unmineable
coal seams, saline aquifers, oil shales and mafic rocks. The first two offer potential
for enhanced oil and methane production, leading to profitable or near break-even
operations. The last three become increasingly costly because using them produces
no valuable co-product and the costs of sequestration increase significantly.
Furthermore, these geologic sites will remain, at best, only promising for storage
of large volumes of carbon dioxide until questions about reservoir heterogeneity
and integrity, brine-rock-gas interactions, acidification and corrosion and related
technical and engineering uncertainties have been studied. Pilot studies are now
underway at many sites to begin to answer these questions.
In our second feature, the Geotimes staff write about some of these projects.
One potential saline aquifer site is the Frio Formation along the Texas Gulf Coast,
as Kristina Bartlett describes in "A Salty Burial." This summer a consortium
of industry, government and academe will inject carbon dioxide into the brine-saturated
aquifer and monitor the invasion and containment of the gas. A similar but much
larger saline aquifer injection has been underway in the North Sea since 1996.
In both cases, researchers want to know how well the aquifer seal contains the
carbon dioxide and the effective capacity of the aquifer as constrained by heterogeneity,
brine-gas-rock reactions and the like. This option is a costly one because it
produces no valuable co-product. But it is attractive because there are so many
In "Oil Fields: Giving and Receiving," Bartlett describes the profitable
transport of byproduct carbon dioxide from the Great Plains Synfuels Plant in
North Dakota to an injection site in the Weyburn oil field in Saskatchewan, Canada.
This process is economical and uses proven technology. It warrants further study
to improve criteria for evaluating other sites. Describing another economically
favorable project, Lisa M. Pinsker, writes in "Value Added in Coal Seams"
about industry injecting carbon dioxide and nitrogen into coal seams in the San
Juan Basin of northwest New Mexico in order to enhance methane recovery. A similar
project is underway in Poland.
Our final feature, "Making Rocks," touches on a very different, less
direct storage method. Christina Reed introduces research on storing carbon dioxide
through chemistry: altering mafic rocks by injecting solutions rich in carbon
This month's Comment, "Milestones in Earthquake Research," is a timely
juxtaposition for our carbon sequestration focus. Robert M. Hamilton tracks the
origins and evolution of the National Earthquake Hazards Reduction Program over
its 25-year history. He identifies two lessons from that history that apply equally
to the nascent carbon sequestration programs. First, success will be favored by
integrating all relevant disciplines, including competing communities. Second,
link research together with information and technology transfer and, simultaneously,
implementation to demonstrate proof of concept and feasibility. I wonder what
a 25-year retrospective of the carbon sequestration industry will look like? Thanks
to you, Bob, and to each of our authors.
Believe your compass,
Samuel S. Adams