Surfactant flooding optimum phase types

Optimum Phase Type and Optimum Salinity Profile in Surfactant Flooding... 

A hne core-scale model is used to study the optimum phase type and optimum salinity prohle in surfactant flooding. 

Surfactant Mixing Rules. The petroleum soaps produced in alkaline flooding have an extremely low optimal salinity. For instance, most acidic crude oils will have optimal phase behavior at a sodium hydroxide concentration of approximately 0.05 wt% in distilled water. At that concentration (about pH 12) essentially all of the acidic components in the oil have reacted, and type HI phase behavior occurs. An increase in sodium hydroxide concentration increases the ionic strength and is equivalent to an increase in salinity because more petroleum soap is not produced. As salinity increases, the petroleum soaps become much less soluble in the aqueous phase than in the oil phase, and a shift to over-optimum or type H(+) behavior occurs. The water in most oil reservoirs contains significant quantities of dissolved solids, resulting in increased IFT. Interfacial tension is also increased because high concentrations of alkali are required to counter the effect of losses due to alkali-rock interactions. 

Kalpakci et al. [13] introduced the concept Low Tension Polymer Flood , LTPF. The flood was conducted by coinjection of surfactant and polymer and, due to chromatographic effects, the polymer moved ahead of the surfactant. In such an application, mobility of the water at the front will be reduced and the activity of the surfactant will be enhanced. The LTPF system should, according to Kalpakci, exhibit type III/II( —) (slightly under optimum) phase behavior at the injection. Ethoxylated... 

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