A crude oil simulant is disclosed that is an emulsion of an organic continuous phase, an aqueous dispersed phase, and an emulsifier. To enhance the biodegradability rate of the simulant various strains of bacteria can be added to the aqueous phase. Nutrients can be added to the aqueous phase to increase activity of the bacteria. The components of the simulant of the invention can be mixed under high shear conditions such as 1,000-12,000 reciprocal minutes. The emulsion based oil simulants can be prepared on-site and can be readily tailored to simulant a wide variety of crude oils under various conditions.