The results of an evaluation of different mixed surfactant and alkaline-enhanced surfactant systems for enhanced oil recovery are described. Several mixed surfactant systems have been studied to evaluate their oil recovery potential as well as improved adaptability to different ranges of salinity, divalent ion concentrations, and temperature. Several combinations of screening methods were used to help identify potential chemical formulations and determine conditions where particular chemical systems can be applied. The effects of different parameters on the behavior of the overall surfactant system were also studied. Several commercially available surfactants were tested as primary components in the mixtures used in the study. These surfactants were formulated with different secondary as well as tertiary components, including ethoxylated and non-ethoxylated sulfonates and sulfates. Improved salinity and hardness tolerance was achieved for some of these chemical systems. The salinity tolerance of these systems were found to be dependent on the molecular weight, surfactant type, and concentration of the surfactant components. Oil displacement experiments in Berea sandstone cores showed considerable improvement in oil recovery potential of these mixed and alkaline-enhanced surfactant systems. Research results have shown the existence of favorable conditions for oil recovery using these two methods. Some of these displacement experiments were conducted with the aid of imaging tools such as NIPER's computer-aided tomography (CT) scanner to determine the progression of the flood. The effectiveness of the surfactant formulation and the mobility control system were monitored using this technique. Several reservoirs were selected as the focus of the research for the application of these improved chemical flooding methods. These reservoirs included North Burbank (OK) Unit, Hepler (KS) Field, and the Government Wells (TX) field. The Burbank reservoir was selected from several Class 1 reservoirs. A database evaluation for this reservoir class was conducted. The Burbank reservoir properties were identified as grouped within the mid-range values for this class. North Burbank retains a significant reserve of unproduced oil and has been identified as a prime candidate for the application of advanced chemical EOR methods.