Effects of Tragacanth Gum as a natural polymeric surfactant and soluble ions on chemical smart water injection into oil reservoirs

Abstract

Recently, the attention of researchers has been drawn to the use of polymeric surfactants in enhanced oil recovery (EOR). These additives in injectable water have both the characteristics of surfactant in interfacial tension (IFT) reduction and polymer in increasing viscosity. Natural polymeric surfactants can also be selected for the researches because they are cheap, available and environmentally friendly. But their performance compared to chemicals and their stability at reservoir temperatures should be considered. In this study, Tragacanth Gum was used as a natural polymeric surfactant in combination with optimum salinity of smart water. Fourier-transform infrared spectroscopy (FTIR) and thermal gravimetric analysis (TGA) were performed to better characterize the polymeric surfactant and measure its stability at reservoir temperatures. IFT, viscosity and flooding tests were also used to measure its application for EOR. Flooding of the optimum fluid was performed at critical micelle concentration (CMC) of the additive and optimum salinity and alkali. The results show that, although the IFT at the CMC has a significant reduction compared to the intermediate level of water and oil this amount is more appropriate at optimum salinity and alkali for EOR processes. Fluid viscosity in CMC also reaches the appropriate values and finally, an increase of 21.4% in the recovery factor is observed by injection of a small volume of optimal fluid.