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

Double tapered surfactant waterflood oil recovery process

Patent ·
OSTI ID:6385287

Disclosed is an oil recovery process for recovering oil from subterranean formations containing relatively high salinity water , said process employing an aqueous surfactant fluid containing at least two surfactants, one primary anionic surfactant such as petroleum sulfonate and a solubilizing cosurfactant such as an alkyl or alkylaryl, polyethoxy sulfate or sulfonate. The process comprises injecting a plurality of slugs of surfactant fluids followed by a low salinity fluid containing a viscosifying amount of a hydrophilic polymer. The salinity and concentration of solubilizing cosurfactant of each surfactant slug are both decreased from the maximum level in the first slug of the surfactant fluid and in successive slugs to a minimum level at the last slug of the surfactant fluid.

Assignee:
Texaco Inc
Patent Number(s):
US 4232737
OSTI ID:
6385287
Country of Publication:
United States
Language:
English