Dilute aqueous “solutions” of anionic surfactants injected during enhanced oil recovery processes usually contain liquid crystalline material. Phase behavior has been studied in a model system containing sodium chloride brine with surfactant, alcohol, and salt contents maintained below 6, 10, and 3 weight percent respectively. Pseudoternary phase diagrams at constant salinities are used to represent the results. Some interpretation of the results is given in terms of micellar shape transformations produced by changes in the relative hydrophilic and hydrophobic properties of surfactant-alcohol mixtures.