Variability in corrosion rates, 0.1 to 10 mm/year, observed in an electrical submersible pump driven subsea pipeline system culminated in a search for a corrosion inhibitor and treatment program that successfully controls the cumulative impact of multiple types of flow and produced solids. The problems arising from these causative factors are further exacerbated by depleting sands that produce increasing CO2 mole fraction, often denoted by an increasing gas oil ratio, coupled with increasing water cuts. These factors act synergistically with multiphase flow corrosion to accelerate damage and cause flow line failure even where corrosion inhibitor has been applied. Presented is a case history of corrosion problems noted, modeling results of flow regime, inhibitor dosage determination from lab tests and success/failures of field treatment programs.