A polymer-injectivity test designed to control mobility in cosurfactant-enhanced alkaline flooding was performed in the Q sand of the White Castle field, LA. Analysis of test data indicates that a polymer bank with an average viscosity of 4 cp was propagated as far as 90 ft into the reservoir with no measurable sign of degradation. It is estimated from pilot and laboratory data that injection of 500 ppm polyacrylamide through perforations at a rate of at least 32 B-D/in.(2) of perforation into gulf coast sands is feasible. Monitoring of backproduced reservoir samples indicates that, to date, no detectable change in viscosity has occurred over a 2-year period.