| abstract |
A novel, thickened, miscible flooding medium to displace petroleum in subterranean reservoirs is a dispersion of light hydrocarbons, water and a surfactant system. The water may have from about 1500 to 12,000 parts per million polyvalent ions such as calcium and/or magnesium. The surfactant system comprises a water soluble salt of an alkyl or an alkylaryl sulfonate plus a water soluble salt of an alkyl or alkylaryl polyethoxy sulfate anionic surfactant plus a nonionic surfactant such as a polyethoxylated alkyl phenol, a polyethoxylated aliphatic alcohol or a fatty acid mono or dialkanolamide. |