The process of recovering residual oil from an oil reservoir by alkaline flooding relies on soap formation by the reaction of the alkali and free long-chain organics acids in the crude oil. In this study, dilute mineral acids were used to liberate additional new organic acids from their nonreactive compounds such as esters, amides, and acid-base complexes present in the crude oil. This was accompanied by an observed enhanced on regenerated interfacial activity of the oil. This acid pretreatment method may be applied to oil reservoirs which have been exhausted by previous alkaline floodings to regenerate activity in the residual oil or to reservoirs never exposed to any alkali contact to give the subsequent alkaline flooding a better first-round recovery. The major technical problem anticipated in applying this process to actual reservoirs is the consumption of acid by the reservoir rock. An analysis was done that showed that sandstone reservoirs with low clay and carbonate content are amenable economically to such an acid treatment. Slug sizes for the acid and water buffer slugs have been estimated using a simple diffusion, comvective dispersion model to ensure that the acid and alkaline slugs do not mix.