As oil reserves are being depleted in the United States, there is an increasing need to recover the trapped oil in the reservoir rock which accounts for up to 60% of the total oil available. This oil may be recovered using chemical enhanced oil recovery (EOR) techniques. In our case study, we investigated viable EOR surfactant/polymer formulations for conditions conducive to high efficiency oil recovery in ultra-low salinity, low temperature, and high hardness reservoirs. Formulations were screened for Winsor Phase I (microemulsions) or Winsor Phase III (bicontinuous emulsions),: both of which are conducive to high efficiency oil recovery. Strong emulsion phase behavior at low salinities was observed in binary surfactant mixtures of anionic alkyl-alkoxy sulfates (at \u3e 16,000 ppm). Using a novel anionic/cationic formulation, emulsion phase behavior was observed at the ultra-low reservoir salinity of 10,000 ppm. These formulations demonstrate industrially viable surfactant/polymer formulations that can used for high efficiency EOR in low temperature-salinity and high hardness reservoirs within the continental United States and abroad