Compounds and compositions are used as corrosion inhibitors for pipelines for crude oil containing water with high salt concentrations. The inhibitors are ionic liquids, imidazoles, benzotriazoles, and mixtures thereof. The composition includes two or more members of the inhibitors with a solvent. The inhibitors reduce corrosion of metallic surfaces of the pipelines containing crude oil having 0.2 and 40 wt % water, 10,000 to 70,000 ppm salt, and 9 to 600 ppm hydrogen sulfide. A synergic effect is provided by two or more different inhibitors. This synergy is derived from interactions with the metallic surface, among themselves or with the corrosive medium depending on the chain length, to inhibit the corrosion with decrease of the formulation dose. The composition can be a ternary formulation of the three families or two components of one family and a third component of a different family.