Low dosage naphthenate inhibitors, such as a surfactant or hydrotrope, delivered into production fluids for contact with mixtures of oil and water, such as in a hydrocarbon producing formation, production equipment, or processing systems. Inhibitor compounds such as monophosphate esters and diphosphate esters exhibit surface-active properties that cause the inhibitors to self-associate at oil-water interfaces and inhibit interactions between organic acids in the oil with cations or cation complexes in the water. These compounds also inhibit aggregation of organic acid carboxylate salts that form when pH and pressure conditions are amenable to organic acid ionization. Preferred inhibitors do not form emulsions due to the formation of unstable mixed interface structures that result in coalescence of dispersed droplets. Naphthenate inhibitor compound dosages of less than 100 ppm can effectively inhibit naphthenate salts or other organic acid salts that can form precipitates or emulsions during crude oil production or processing.