1. n. [Enhanced Oil Recovery]

A distinction among three phase behaviors of oil, water and surfactant systems when they form a microemulsion. The salinity of the brine phase is an important parameter influencing which type of behavior occurs. To test for the type of system, surfactant is added to an oil-water system. In a Winsor Type I system, the surfactant forms an oil-in-water microemulsion in the aqueous phase. This behavior is not favorable to achieve ultralow interfacial tension with surfactants. In a Winsor Type II system, the surfactant forms a water-in-oil emulsion in the oil phase. This behavior leads to surfactant retention in the oil phase and is unfavorable for an enhanced oil recovery (EOR) process. In a Winsor Type III system, the surfactant forms a microemulsion in a separate phase between the oil and aqueous phases. This phase is a continuous layer containing surfactant, water and dissolved hydrocarbons. This situation is ideal to achieve ultralow interfacial tension values and is favorable for EOR.

See: microemulsion