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

Abstract

The setup utilizing an X-ray scanner and Raman spectrometer is used for the characterization of CO2/CH4 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 CO2 displacing CH4 and CH4 displacing CO2 is measured. It is showed that mixing is higher at the core entry than core exit. Mixing for CO2 as a displacing fluid is higher than for CH4 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.