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

Process for treatment of water injection wells

Patent ·
OSTI ID:7215966

Low permeability reservoirs (under 20 md) can be flooded for oil recovery by an oil-external micellar slug, preceded and followed by micellar (buffer) slugs of higher water content, and driven by a waterflood. The buffer slugs protect the micellar slug from contact with water which would cause a formation blocking emulsion. A fresh water preflush is desirable to displace reservoir water containing several hundred ppm of divalent ions. The salt concentration of the micellar slug is 5,000 to 20,000 ppm. To increase the system's resistance to emulsification, the ratio of cosurfactant to surfactant concentration should be higher in the first and last buffer slugs. The micellar slug consists of kerosene, a hydrocarbon sulfonate (surfactant), an ethoxylated aliphatic alcohol and a C/sub 5/ alcohol or fused oil, water, and sodium chloride.

Assignee:
Amoco Production Co.
Patent Number(s):
US 3670819
OSTI ID:
7215966
Country of Publication:
United States
Language:
English