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U.S. Department of Energy
Office of Scientific and Technical Information

Steam-foaming surfactant mixtures which are tolerant of divalent ions

Patent ·
OSTI ID:6759302

This patent describes a process in which oil is displaced by injecting steam and steam-foaming surfactant into a subterranean reservoir. The reservoir has an ion-exchange capacity capable of reducing the rate of propagation of the surfactant through the reservoir due to a tendency for polyvalent cations from ion-exchange sites within the reservoir to be exchanged for monovalent cations dissolved in the injected fluids. An improvement is described for enhancing the rate of surfactant propagation which comprises: injecting a reservoir-tailored steam-foaming surfactant mixture consisting essentially of (a) a predominant amount of a sulfonate surfactant which, by itself in the presence of the reservoir oil and in the absence of polyvalent cations, is capable of yielding a steam foam of significantly reduced mobility, and (b) a lesser amount of an alkylpolyalkoxyalkylene or an alkylarylpolyalkoxyalkylene sulfonate surfactant which is effective for causing the steam-foaming surfactant mixture to be capable of yielding a steam foam of significantly reduced mobility in the presence of the reservoir oil and the ion-exchangeable cations on the reservoir rocks.

Assignee:
Shell Oil Co., Houston, TX
Patent Number(s):
US 4643256
OSTI ID:
6759302
Country of Publication:
United States
Language:
English