Abstract
The selection of appropriate surfactants for improving oil production in chemical flooding relies considerably on the values of the interfacial tension (IFT) between surfactant solution and crude oil. This paper presents a study on the impact of the dynamic IFT on emulsifying capacity and oil production improvement. The dynamic IFT behaviors of anionic, nonionic, cationic and zwitterionic surfactants were measured against a light crude oil using a spinning drop tensiometer, and classified into two categories. A pair of surfactants with a similar equilibrium IFT value but different initial values were selected for comparative studies. The emulsification results suggest that the instantaneous emulsification, a key mechanism for oil mobilization, is mainly attributed to a quick initial IFT reduction, affecting oil productions. The results of micromodel tests using surfactants and coreflooding oil displacement experiments using surfactant-polymer mixtures indicate that the system has low initial IFT value achieves significantly higher incremental oil production than the system that has high initial IFT value. This suggests the surfactants that are able to reach quick initial IFT reduction are preferential for improving oil production applications.
NSTL