Abstract: A method for the recovery of oil from an oil-containing subterranean formation by waterflooding employing as an injection medium an aqueous solution of an anionic surfactant comprising a hydrocarbyl substituted succinimido aryl sulfonate and/or its succinamic acid derivative. Such surfactants retain their detergency and do not precipitate in aqueous systems containing high concentrations of brine, e.g., over 20,000 ppm Ca.sup.++, over 10,000 ppm Mg.sup.++ and over 50,000 ppm Na.sup.+. These surfactants are effective in mobilizing tertiary oil under highly saline environments and demonstrate low adsorptive losses. When used as cosurfactants, these materials significantly improve the brine tolerance of more sensitive surfactants, such as petroleum sulfonates.

Abstract: Alkyl lactone esters or sulfidic esters are prepared by reacting an alkenylsuccinic anhydride with an alcohol or thiol in the presence of an acid-acting catalyst. The esters are useful as dispersants or detergents in aqueous or hydrocarbon systems or they may be further reacted with amines to produce other useful additives for such systems. Esters of monohydroxy alcohols or monothiols or polyhydroxy alcohols or polythiols may be prepared and used in this invention.