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Institute of Hydraulic Engineering


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Numerical Investigation of CO2 Sequestration in Geological Formations - Problem-Oriented Benchmarks
Project manager:Prof. Dr.-Ing. Rainer Helmig
Deputy:Dr.-Ing. Holger Class
Research assistants:Dr.-Ing. Anozie Ebigbo
Duration:1.4.2005 - 31.3.2008
Funding:The project is funded by the externer Link Federal Ministry of Education and Research (BMBF) and the externer Link Deutsche Forschungsgemeinschaft (DFG) in the context of the geoscientific research and development programme externer Link GEOTECHNOLOGIEN.
Project Partners:

This project is part of the research area:
Modeling of multiphase-multicomponent processes for the sequestration of CO2 in the subsurface

Publications: Link


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 greenhouse 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 example,

  • 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 international workshop. 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.