Coreflooding of clay-containing sandstones can yield substantial additional recovery by reducing the flood brine salinity, associated with a shift towards water-wetting. X-ray micro-CT and image analysis were used to determine the pore-scale distribution of residual oil in restored, reservoir sandstone mini-plugs after high and low salinity flooding, to aid in identifying the microscopic displacement mechanisms of tertiary recovery.
In this Talk, I will present two low salinity projects that I did during my PhD studies at ANU. The first one is low salinity studies of outcrop sandstones in imbibition mode and the second one is water flooding studies of reservoir sandstones in high and low salinity in flooding mode. In these two projects we took advantages of micro-CT difference tomograms as well as main tomograms. Main micro-CT tomograms were dry, high salinity, low salinity and brine saturated states. Image analysis of main and difference tomograms were utilised to understand mechanisms behind low salinity flooding. For this purpose, we studied oil saturation distribution, quantitative oil recovery, surface area of oil/brine/rock and surface curvature of oil and brine inside porous media after high and low salinity water flooding.