Properties and oil displacement efficiency of new type salt tolerance wormlike micelles

Key words:  wormlike micelle  salt tolerance  viscoelasticity  oil/water interfacial tension  oil displacement efficiency

Abstract:

Two types of wormlike micelles systems were prepared using zwitterionic (N-hexadecyl-N,N-dimethyl-3-ammonio-1-propane sulfonate, HDAPS), anionic (sodium dodecyl sulfate, SDS) surfactants, and chemical additive at high salinity simulated water, which are HDAPS-SDS system and HDAPS-SDS with 0.2% auxiliary chemical mixed system, respectively. And the viscoelasticity, properties of reducing oil/water interfacial tension, as well as the oil displacement efficiency of the wormlike micelles were investigated. It is found that the viscosity of 0.73% mass fraction HDAPS-SDS system is 42.3mPa·s at 60℃, and the minimum dynamic interfacial tension between crude oil and water is 6.0×10-2 mN·m-1. By adding 0.2% chemical additive, the viscosity of 0.73% HDAPS-SDS is increased to 51mPa·s, and the oil/water interfacial tension is reduced to ultralow level of 6.7×10-3 mN·m-1. Due to the dual functions of mobility control and reducing the oil/water interfacial tension, the two new wormlike micelles present good oil displacement efficiency as flooding systems.