Emulsion oil recovery process usable in high temperature, high salinity formations

摘要

Many petroleum formations contain water having high salinity and/or high concentrations of divalent ions such as calcium or magnesium dissolved therein, and are additionally at temperature from about 70 DEG F. to about 300 DEG F. Most surfactants and polymers suitable for use in fluids or emulsions used in oil recovery operations are either ineffective in high salinity or high hardness waters, or cannot tolerate the higher temperatures encountered in many such formations. A water-external phase, viscous emulsion containing a water soluble and/or dispersible alkylpolyalkoxyalkylene sulfonate or alkylarylpolyalkoxyalkylene sulfonate and as a phase stabilizing additive, a water dispersable and/or soluble petroleum sulfonate, is an effective fluid for flooding oil formations containing brine whose salinity is from 70,000 to 220,000 parts per million total dissolved solids and also having temperatures as high as 300 DEG F. The emulsion is phase stable over a wide range of formation temperatures and water salinities and hardness values.