Experimental Investigation on the Effect of Brine Salinity and Polymer Concentration on the Fluid/Rock Interactions of Sandstones

Low-salinity polymer flooding (LSPF) is one of the chemical EOR methods that has received considerable attention in recent years in both sandstone and carbonate reservoirs. In this method, low-salinity water improves the oil production efficiency by changing the wettability of the rock from oil-wet to intermediate-wet or water-wet, and polymer improves the macroscopic sweep effiency by providing appropriate mobility. The main goal of this research is to investigate the effectiveness of hybrid low salinity and polymer on changing the fluid/rock properties (i.e. contact angle) of specific oil/rock/brine system from southwest Iran. From the experimental results, in the presence of seawater (SW ) aged substrates show a strong oil-wet behavior. Even after adding polymer (500 ppm and 1000 ppm) the changes in contact angle were not significant. However, with reducing the salinity of water by about 10 times (10xdSW), the change of contact angle was considerable. For example, in the case of quartz/crude oil/10xdSW+1000 ppm HPAM the contact angle changed from about 175°, to the ultimate value of 90° after 60 hours.