Study of oil displacement performance of hydroxyl sulfobetaine surfactant

In this paper, new alkali-free hydroxyl sulfobetaine surfactant designed for the target oil reservoir in our laboratory was used. The interfacial tension property, emulsifying capability, peeling the oil film between surfactant/polymer binary oil-displacing system and the target crude oil and the viscosity of the system were investigated systematically. Finally, oil-displacement capacity of the binary oil-displacing system on the target reservoir's natural cores was discussed. The experimental results indicated under the actual condition of the target oil reservoir with total salinity ranging from 4694mg/L to 24270mg/L and temperature being 50 degrees C, the surfactant/polymer binary oil-displacing system with surfactant mass fraction ranging from 0.025% to 0.2% and polymer mass fraction of 0.15% could reach ultra-low interfacial tension with the target crude oil rapidly. The surfactant/polymer binary system above mentioned could emulsified crude oil easily and the volume fraction of WinsorIII middle phase microemulsion could be up to 53.06%. It also could peel the oil film adhered to oil-wet quartz plate quickly and increase the viscoelastic of surfactant/polymer binary oil-displacing system slightly. The displacement experiments made by using natural core in the target oil field indicated that oil recovery was improved by 15% after water flooding. All these results showed that hydroxyl sulfobetaine surfactant had a good potential for flooding in EOR.