Hypothesis: The attainment of ultralow interfacial tensions between crude oil and injected aqueous surfactant mixtures is a prerequisite for an effective chemical Enhanced Oil Recovery (EOR). The dynamic Phase Inversion Temperature (PIT) of SOW emulsified systems is very close to the "optimum temperature" currently identified with equilibrated SOW systems. Therefore, the PIT could be a tool to track the "optimum formulation" and determine EACN of crude oils. Additionally, the PIT-slope method could be used to characterize EOR surfactants. Experiments: The PIT of 3% C10E4/crude oils/water emulsions are compared to the PIT for n-alkanes in order to estimate crude oils EACN. The "PIT-slope" method is applied to different non-ionic and ionic extended EOR surfactants to assess their amphiphilicity. The conductivity profiles of different EOR surfactants/crude oil/NaCl(aq) emulsions at f(w) = 0.5 are determined at different salinities. Findings: Considering the PIT shifts and shapes, it is possible to infer relevant information on the crude oil such as precise EACN and relationships between optimum salinity and temperature. The "PIT-Slope method" allows ranking EOR surfactants according to their amphiphilicity. Mixing both results allows a faster determination of key parameters used in EOR compared to studies with equilibrated system. (C) 2019 Published by Elsevier Inc.