Analysis of carbon dioxide/methane mixing process in rock cores for natural gas storage sites with carbon dioxide cushion

The setup utilizing an X-ray scanner and Raman spectrometer is used for the characterization of CO 2 /CH 4 mixing process in rock core samples. The setup allows us to determine mixing in the core and the mixing at the core-entry/exit. The mixing coefficinet for both CO 2 displacing CH 4 and CH 4 displacing CO 2 is measured. It is showed that mixing is higher at the core entry than core exit. Mixing for CO 2 as a displacing fluid is higher than for CH 4 as displacing fluid. A Berea sandstone rock core was used for measurement optimization. Dispersion coefficients for samples from a location perspective for an Underground Gas Storage in an aquifer with CO2 cushion in Poland were determined.