Synergistic Effects of Microbial Polysaccharide Mixing with Surfactant on Enhanced Oil Recovery

Biopolymer flooding is one of the most recently developed technologies to enhance oil recovery (EOR). A novel exopolysaccharide named WL is produced by members of the genus Sphingomonas sp. WG. WL was mixed with a nonionic surfactant (BE1). The FTIR measurements of the mixture were systematically investigated. Moreover, the rheological properties of WL-BE1 were observed to be maintained under high temperature and high salinity conditions. This paper compared the enhanced oil recovery with WL and WL-BE1. The test showed: the two inflection points on the surface tension curve indicated intermolecular interactions between WL and BE1. The combination of WL and BE1 resulted in the formation of networks in the solution through electrostatic and hydrogen bonding interactions. Additionally, the mixture maintains stable rheological properties even under high-temperature and high-salinity conditions. The mixtures of WL-BE1 system could enhance the oil displacement efficiencies by 24.73%, respectively. It has been proven that the combination of exopolysaccharides with surfactants can enhance the process of oil recovery through their synergistic effects.