25th International Meeting on Organic Geochemistry IMOG 2011

O-55
The organic geochemistry of carbon management
Steve Larter, Thomas Oldenburg, Haiping Huang, Ian Gates, Barry Bennett, Norka
Marcano
PRG, University of Calgary, Calgary, Canada (corresponding author:slarter@ucalgary.ca)
We review current and future organic geochemical
applications to managing carbon emissions
associated with fossil fuel recovery and use. While
low carbon fuel alternatives are urgently needed, the
slow deployment of new energy generation
technologies means fossils fuels will be burnt for
decades. Decarbonising fossil fuel usage has a major
geochemical component with geochemical
applications in the areas of:-
1. Carbon efficient recovery and processing of
fossil fuels such as oil, gas and coal (CERP).
2. Industrial carbon dioxide capture and
storage in subsurface reservoirs (CCS).
3. Geoengineering for removal of carbon
dioxide from the atmosphere via air capture
or accelerated rock weathering (GCDR).
Organic geochemical applications are of several
types. In the CERP area there are many traditional
applications relating to assessment of resource type
and fossil fuel recovery. Thus petroleum systems
studies are used to improve energy recovery and
emissions efficiency. The many established
geochemical methodologies are not discussed here.
Recovery of unconventional oil and gas is an
increasing component of energy production and the
organic geochemistry of heavy oil and shalegas is
intimately involved with its efficient recovery.
Assessment of oil biodegradation and fluid properties
vertically and laterally in reservoirs is a direct input
into well placement and operational decision making
and we describe case histories showing how organic
geochemistry is used as a direct input into reservoir
engineering practices. A key factor is the conversion
of geochemical measurements and concepts to inputs
relevant to reservoir engineering protocols. The
commercial application of organic geochemistry to
real time production problems has required invention
of several new methods of sample extraction and
these are described. A potential game changing area
in CERP is the gasification, in situ of heavy oil or
coals. Methane has half the CO2 emissions of coal for
the same amount of energy generation. While thermal
gasification of coal is well developed and microbial
conversion of oil to methane has been researched for
energy recovery, the commercial conversion of coal to
methane microbiologically is still in its infancy with
rudimentary understanding of the processes involves.
Even the details of which compounds are being
degraded remains poorly described. We examine
progress and the need for new analytical
methodologies such as FTMS, looking theoretically at
organic geochemical and mass transport bottle necks
to large scale in situ microbial gasification of coal at
rates sufficient to replace coal mining and burning.
In the CCS storage area, inorganic geochemical
applications related to the CO2-bicarbonate-carbonate
system are self evident. Organic geochemical
applications are less obvious, but organic
geochemists may have great interests in economic
production and biogeochemical fates of some of the
alternative insoluble carbon storage vectors such as
whewellite (calcium oxalate) or DOM analogs, or in
biogeochemical routes to enhanced aqueous CO2
dissolution rates which have been proposed. We
review new organic geochemical focii in the carbon
storage area.
It is likely humankind will not get its act together in
time and that emergency carbon dioxide reduction
procedures may be needed mid century. Such
processes are termed geoengineering and if done
geochemically, can be at the safer end of that
technology domain. While organic geochemistry is
unlikely to be important in large scale air capture of
CO2, it may be crucially important in understanding
how to biologically accelerate carbon dioxide-mineral
reactions as a means of large scale atmospheric CO2
removal. Thus the biogeochemistry of mineral
carbonation reactions is a potential growth area for
organic geochemists.
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