The mitigation of the greenhouse effect is an
explicit goal that was formulated at the climate conferences in Kyoto, 1997,
and New Delhi, 2002. Besides strategies for reducing the emissions of
gases into the atmosphere, which should obviously be of highest priority,
the discussion about CO2 storage in geological formations
(CO2 sequestration) has also emerged recently.
The idea is to separate CO2 from flue gases and dispose it in the
subsurface, e.g. in deep saline aquifers which are of no economic value due
to their depth and salinity. Obviously, depleted natural oil and gas reservoirs
are also potential sites for CO2 storage.
An economically interesting technology could be the storage of CO2 in
unmineable coal seams and the simultaneous production of CH4 (Enhanced
Coalbed Methane - ECBM).
Although the injection of fluids into deep subsurface layers is a technology
that has already existed for some decades,
there are still important issues to be addressed before
a large-scale implementation is justifiable. Such questions concern, for
- the available storage capacities in aquifers, oil/gas fields, or coal seams,
- the expected leakage rates from CO2 disposals through the overlying formations
or natural and anthropogenic fault zones (fractures, abandoned wells),
- a better understanding of the physical storage mechanisms like free-phase trapping,
for example, in depleted oil and gas reservoirs, hydrodynamic trapping in deep brine
aquifers, solubility trapping in the formation brines, adsorption trapping in coal seams etc.
The aim of this research project is to apply recently developed numerical and
analytical concepts to address different problems related to sequestration scenarios.
Comparisons between numerical studies and analytical analyses as well as intercomparisons
of different codes are essential
- [(i)] to improve the understanding of the complex coupled processes
taking place in the formations and
- [(ii)] to explore the accuracy and reliability of the models.
Benchmarks that address characteristic problems related to CO2 storage in the
subsurface have been defined and are expected to help create a common basis for the discussion of the
main aspects, open questions, risks, and chances among experts. We also consider it
important to study the most relevant processes concerning the issues discussed above by
conducting sensitivity analyses with example problems on different scales.
The ultimate goal of the project is to present the benchmarks and their results to the
scientific community and discuss them in an
Since the time for finding solutions to the
climate problems is short, such international
communication, cooperation, and exchange between the leading researchers in this field
provides an essential basis for further development and investigation strategies.