Sub pore-scale investigation of wettability alteration during low salinity water flooding
Volume Title: 1
1Department of Chemical and Petroleum Engineering, Sharif University of technology, Tehran, Iran
2Institute of Petroleum Engineering, School of Chemical Engineering, College of Engineering, University of Tehran, Tehran, Iran
Scale deposition due to the injection of incompatible fluids has been a challengeable issue in the oilfield operations. Deposition process generally associated with the porosity and permeability reduction of the reservoir rock. In current study, a series of experiments conducted to investigate the effect of ion concentration and salinity of the injected brine on the total amount of CaSO4 precipitation. The water compatibility tests were performed to evaluate two different mechanisms of inorganic scaling; mixing of incompatible water and the rate of injection. Therefore, contact angle measurement was utlized to examin the effect of scaling process on the wettability. Based on the results obtained here, the amount of CaSO4 precipitation increases as the concentration of SO42- ions in the injected brine was increased from ½ to 1 times of its original concentration. Even though, the increasing of Ca2+ ions in sea water increases the CaSO4 scaling, the presence of Mg2+ ions in sea water increases the solubility of CaSO4, inhibiting the scale deposition This study also showed that, the rate change is the dominant parameter in scaling formation. By increasing the rate of SW, the amount of solubility of CaSO4 was increased.
Water flooding; Scale precipitation; Potential determining ions; Contact angle; Wettability alteration; Enhanced Oil Recovery