Micellar slug for oil recovery

摘要

A micellar slug for use in the recovery of oil, the slug containing a hydrocarbon, an aqueous medium, a surfactant, and a cosurfactant. The surfactant contains as an essential component an internal olefin sulfonate having 10 to 26 carbon atoms and a disulfonate content of about 20% by weight or less. This micellar slug has an excellent capability for decreasing an interfacial tensions between oil and micro-emulsions and between water and micro-emulsions and an excellent salinity tolerance and hard-water resistance. Furthermore, the stable micro-emulsion from this micellar slug can be maintained during sweeping in subterranean reservoirs even when the salt concentration of the subterranean water is changed.