High conformance oil recovery process
The conformance of a water flood oil recovery process, including surfactant or other chemicalized water flood process, in a formation containing at least two zones of varying permeability, the permeability of one zone being at least 50% greater than the permeability of the other zone, is improved by water flooding until the higher permeability zone has been depleted, after which a fluid is injected into the high permeability zone, said fluid having relatively low viscosity at the time of injection and containing a particular surface-active agent which promotes the formation of a coarse emulsion in the flow channels of the formation which reduces the permeability of the high permeability zone. Since the viscosity of the fluid injected into the previously water flooded, high permeability zone is no greater than water, it is injected easily into the zone and moves through substantially the same flow channels as water would move in the formation. After the permeability of the first zone has been reduced substantially, water flooding may then be accomplished in the second zone which was originally not invaded by the injected water since its permeability was substantially less than the permeability of the first zone. The surface-active agent may be tailored to exhibit optimum emulsion formation properties with the particular aqueous fluid present in the flow channels of the formation to be treated.
- Assignee:
- Texaco, Inc.
- Patent Number(s):
- US 4161983
- OSTI ID:
- 6040075
- Resource Relation:
- Patent File Date: Filed date 22 Dec 1977
- Country of Publication:
- United States
- Language:
- English
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