Abstract

---

Ionic liquids have attracted attention in lowering the interfacial tension between oil and water.Several researches were conducted on these materials and possibility of using them in enhanced oil recovery. In this paper, the effect of using a polymer buffer behind a slug size of ionic liquid during flooding was investigated. Ionic liquid solution was prepared with suitable concentration and salinity. Partially Hydrolyzed Polyacrylamide Polymer (HPAM) was used in preparing polymer solutions. Core flooding runs were performed using slug sizes of ionic liquid followed by polymer buffers having different slug sizes, polymer concentrations, salinities, temperatures and injection rates. The results showed that an injection of a polymer buffer after a slug size of ionic liquid increased the amount of the produced oil significantly. The larger polymer buffer slug size,the larger amount of produced oil. Increasing of salinity and injection rate greatly affect polymer efficiency in the improvement of oil recovery. Rising of polymer concentration may plug the pores and as a result, the amount of oil recovery is not a considerable. Although, increasing of temperature decreases oil viscosity and enhances ionic liquid efficiency, the temperature accelerates polymer thermal degradation and consequently lowers the ultimate oil recovery. High injection rate causes mechanical polymer degradation and displacing fluid bypass over oil, consequently low oil recovery can be obtained.