Abstract: A method of extracting hydrocarbons from a subterranean formation includes injecting a surfactant composition into the subterranean formation and collecting hydrocarbons displaced by the injected surfactant composition. The surfactant composition can have at least one polyamine surfactant compound of formula R1R2NA(RNA)xNR3R4, where x is an integer from 0 to 3, R1, R2, R3, R4 and each R are independently a hydrogen atom or an alkyl group, each A is an alkylene group, and the total number of carbon atoms in the surfactant compound is from 10 to 21. The surfactant composition can include liquid or supercritical carbon dioxide.

Abstract: The invention relates to a method of extracting hydrocarbons from a subterranean formation, comprising: —injecting a surfactant composition into the subterranean formation, and —collecting hydrocarbons displaced by the injected surfactant composition; wherein the surfactant composition comprises at least one surfactant compound of formula (I): wherein x is an integer from 0 to 3, R1, R2, R3, R4 and each R are independently a hydrogen atom or an alkyl group, each A is an alkylene group, and the total number of carbon atoms in the surfactant compound of formula (I) is from 10 to 21. The invention also relates to a composition comprising liquid or supercritical carbon dioxide and at least one surfactant compound of formula (I).