Synthesis of temperature-resistant and salt-tolerant surfactant SDB-7 and its performance evaluation for Tahe Oilfield flooding (China)

In order to improve the enhanced oil recovery of high-temperature and high-salt oilfields, a novel temperature-resistant and salt-tolerant surfactant (denoted as SDB-7) was synthesized and evaluated for the Tahe Oilfield (Xinjiang, China), which is representative of high-temperature and high-salt oilfields. It has a central reservoir temperature of 140 degrees C and salinity of 22.6x10(4) mg/L. The temperature-resistant and salt-tolerant performance. interfacial activity, oil displacement efficiency, aging properties. and adsorption properties of the synthesized surfactant were evaluated for Tahe Oilfield flooding. The results showed that the SDB-7 was temperature-resistant and salt-tolerant capacity of 140 degrees C and 22.6x10(4) mg/L, respectively, oil displacement efficiency under static condition of 84%, and adsorption loss of 0.4 mg/g (less than 1 mg/g-oil sand). In the heat aging experiment (under the temperature of 140 degrees C for 60 days), the oil-water interfacial tension and oil displacement efficiency of SDB-7 were almost unchanged. The oil displacement experiments showed that, under the temperature of 140 degrees C and the salinity of 22.6x10(4) mg/L. the surfactant SDB-7 can enhance oil recovery by 14.5% after water flooding.suggesting that SDB-7 has a promising application in high temperature and high salinity (HT/HS) reservoir.