Permeability evolution in sandstone due to injection of CO2-saturated brine or supercritical CO2 at reservoir conditions

Abstract

We measured the change in permeability of two selected sandstones (Berea, Fonteinebleau) due to injection of CO2-saturated (“live”) brine, unsaturated (“dead”) brine or supercritical (sc) CO2 at reservoir conditions. We found that the permeability did not significantly change in a clean sandstone consisting of pure quartz (Fonteinemebleau) due to live or dead brine injection, although permeability changed due to scCO2 injection by ~23%. The permeability in the Berea sandstone, however, changed due to live or dead brine injection, by up to 35%; this permeability reduction in Berea sandstone was likely caused by fines release and subsequent pore throat plugging as the damage was more significant at higher injection rates. We expect that this phenomenon – i.e. rock permeability reduction due to CO2 injection into the formation – can have a significant and detrimental influence on CO2 injectivity, which would be reduced accordingly.