Abstract:
Improved oil recovery by flooding subterranean formations with micellar dispersions; comprised of hydrocarbon, water, cosurfactant, electrolyte, and petroleum sulfonate obtained by sulfonating whole or topped crude oil; is obtained by incorporating within the micellar dispersion about 1. 5 to about 4. 5 wt. % of active sulfonate groups (e. g. --SO. sub. 3 NH. sub. 4 or --SO. sub. 3 Na) which are attached to the petroleum sulfonate. The micellar dispersions of this invention contain an amount of cosurfactant in excess of the amount required to produce a viscosity maximum with the particular micellar dispersion.