1. Correlation between phase behavior and IFT Leslie Zhang

2. Phase behavior after 2 months with 0.2% (left) and 0.5% (right) NI blend.

3. Solubility ratios of 0.2% NI blend / 1% Na 2 CO 3 / NaCl

4. Huh Correlation, 1979 interfacial tension between excess oil or aqueous phase and middle phase, R l3 : solubility ratio of oil or water by surfactant c: a constant with a typical value of 0.3.

5. Comparison of IFT measured by spinning drop measurements using standard procedure and that estimated by Chun-Huh correlation of 0.2% NI blend/1% Na2CO3/NaCl. c=0.3.

6. Solubility ratios of 0.5% NI blend / 1% Na 2 CO 3 / NaCl

7. IFT estimated by Chun-Huh correlation of 0.5% NI blend/1% Na2CO3/NaCl, c=0.3.

8. Phase behavior of 0.2% NI blend/1% Na2CO3/x% NaCl, 40 days of settling. Thin creamed oil-rich layers exist at salinity of 2-3.4% NaCl.

9. Conclusions The measured low IFT over a wide range of salinity is consistent with the solubility ratio data. The thin layer of oil-rich emulsion may be responsible for the above observation. The dependence of this layer on the amount of oil present suggests that it may be due to the presence of the naphthenic soaps.