MULTIVALENT ION TOLERANT STEAM-FOAMING SURFACTANT COMPOSITION FOR USE IN ENHANCED OIL RECOVERY OPERATIONS

摘要

A method for recovering hydrocarbons from a reservoir during gas injection into the reservoir comprises at least periodically injecting a gas comprising steam and a foam-forming composition which includes at least one steam foam diversion surfactant into a reservoir which contains at least one multivalent cation. The foam forming composition comprises water, an effective foam-forming amount of the surfactant which preferably comprises an alkyl aromatic sulfonate and a precipitation control additive. This precipitation-control additive preferably comprises an alpha-olefin sulfonate dimer (AOSD). The method further comprises contacting the hydrocarbons in the reservoir with the foam and the gas so as to assist in the recovery of hydrocarbons from the reservoir.