Elektrische Phänomene bei der Kohlendioxid-Verpressung auf der Laborskala im Hinblick auf ein elektromagnetisches Monitoring

• Antragsteller: Professor Dr.-Ing. Jens-Uwe Repke; Professor Dr. Klaus Spitzer
• Fachliche Zuordnung: Physik des Erdkörpers
• Förderung: Förderung von 2012 bis 2015
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 221782423

In this project, we investigate electrical phenomena occurring during the sequestration of CO2. For this purpose, laboratory experiments are carried out in a cooperation of geophysicists and process engineers at the TU Bergakademie Freiberg. The project is supported by and cross-linked with relevant working groups from the University of Bonn and the Geoforschungszentrum Potsdam. The aim of the project is to generate a knowledge base, which allows the reliable interpretation of electromagnetic data with regard to CO2 monitoring. The electrical signal during the sequestration process is generated mainly through the displacement of saline pore water by resistive CO2. Preliminary investigations provided evidence to this assumption in a qualitative way, but also indicated that simple models do not sufficiently describe the observed effects with respect to physico-chemical processes. At least two contrary effects have been identified: The decrease in electrical conductivity by replacement of saline pore water with CO2 and the increase in conductivity by dissolution and dissociation of CO2 providing additional charge carriers. With the help of a validated petrophysical model, the determination of the CO2 saturation of the pore space should be possible since the electrical conductivity is highly sensitive to the pore content. The proposed research uses both clean sands and standardized pore waters and, thus, enables us to systematically measure electrical and chemical parameters in-situ and in real-time without disturbing side effects due to site specific mineralogy or formation waters. We will investigate both the electrical conductivity of CO2-rich waters and the spectral electromagnetic parameters of sand probes which are perfused by CO2 at pressures up to 30 MPa and temperatures up to 80°C. The results will provide a generalizable, multi-disciplinary interpretation reference and a comprehensive data set of the electrical phenomena related to the binary system CO2/water in porous media. They represent the petrophysical basis for the subsequent development and design of an electromagnetic monitoring technique.

• DFG-Verfahren: Sachbeihilfen
• Beteiligte Personen: Dr. Georg Nover; Dr. Erik Spangenberg