The toroidal porous plate: a new method to facilitate waterflooding

Abstract

We present a modified porous plate core flooding apparatus where the porous plate has a hole drilled through its centre resulting in a toroid shape similar to a British Polo peppermint, an American Life Savers candy, or a doughnut. The apparatus allows primary drainage and imbibition (water flood) flow sequences to take place sequentially, without the need to remove the sample. During primary drainage the modified porous plate behaves in the same way as a solid, unmodified, porous plate. The method used to isolate the water flood flow line passing through the centre of the porous plate is effective and the plate can withstand capillary pressures up to 5 bar. During water flooding the porous plate is effectively bypassed, with the pressure drop recorded consistent with that across the core-plug alone.We use this new apparatus to measure the relationship between initial and residual non-wetting phase saturations. Sandstone and carbonate rocks are investigated for both decane-brine and CO2-brine fluid systems at elevated temperatures and pressures. The challenges of effectively sealing the hole through the porous plate during drainage are discussed and additional suggestions for future improvements to the design are proposed.