Steady-state supercritical CO2 and brine relative permeability in Berea sandstone at different temperature and pressure conditions

摘要

We measure steady-state two-phase supercritical CO2-brine relative permeabilities in a 61 cm-long Berea sandstone core at three different conditions (40 degrees C and 12.41 MPa, 40 degrees C and 8.27 MPa, and 60 degrees C and 12.41 MPa) under primary drainage. We use pressure taps to obtain pressure drops of individual sections of the core, and X-ray Computed Tomography (CT) to obtain in situ saturation profiles, which together help to mitigate the capillary end effect. We include previously measured relative permeabilities at 20 degrees C and 10.34 MPa, and compare all the data using both an eye-test and a statistical test. We find no appreciable temperature and pressure dependence of CO2 relative permeability within 20-60 degrees C and 8.27-12.41 MPa. We find slight changes in the brine relative permeability between supercritical CO2 conditions (40-60 degrees C and 8.27-12.41 MPa) and the liquid CO2 condition (20 degrees C and 10.34 MPa). The temperature and pressure independence of CO2 relative permeability has been previously recognized and reassured in this work using a capillary-effect-free method. This allows one to use a single CO2 relative permeability curve in modeling two-phase CO2 flow within 20-60 degrees C and 8.27-12.41 MPa.