Enhanced Performance of Low Salinity Water Flooding Process Using Potassium Based Monovalent Salt

Various laboratory experiments and field tests have demonstrated the impact of low salinity in different types of rock samples and reservoirs as a successful phenomenon in improving the oil recovery. This paper aims to study the effects of low salinity solutions of monovalent salt (Potassium Formate (HCOOK)) to achieve higher oil recovery for a specifically designed crude oil – brine – reservoir (COBR) system. The effect of HCOOK on interfacial forces, wetting characteristics and oil displacement potential was investigated on various salts concentration (1000 ppm to 100000 ppm). The surface tension and interfacial tension (IFT) between Low Salinity Water (LSW) and crude oil was measured using surface tensiometer (KYOWA DY-500) via Du-Nouy ring method. Sessile drop experiments were carried out to examine the wetting behaviour of the sand pellet mixed with different clay concentration (25, 50, 75 wt %). Methylene blue test and X-ray Fluorescence (XRF) was performed to obtain the cation exchange capacity and the major oxides of the elements present in the clay respectively. Finally, sand column mixed with the clay fraction was injected with LSW to explore the oil mobilization potential for salt. It was observed that the surface tension value of distilled water reduced from 72.6 mN/m to 54.35 mN/m for HCOOK at 4000 ppm of salt solution. IFT between LSW and crude oil was found to be 35.44 mN/m in case of distilled water which reduced to 28.71 mN/m for 4000 ppm of HCOOK. Moreover, ionic solution effectively modified the wetting behaviour of the sand pellet. Furthermore, Water injection yielded ~45% of the total oil recovery, which increased to ~53%, corresponding to LSW (4000 ppm HCOOK) injection.The experimental results of the study showed that the LSW injection could provide better oil recovery in an eco-friendly and economical way unlike other conventional methods and its aspects can further be explored and engineered to design a more optimum solution to obtain better efficiency during water injection.