| 摘要 |
<p>Recovery of oil from a subterranean formation having a formation temp. of 70-300 degrees F and contg. formation water with a salinity of 70,000-220,000 ppm. total dissolved solids (TDS) is carried out by surfactant flooding. The flooding medium comprises an aq. phase-stable surfactant-contg. fluid with a salinity of 70,000-220,000 ppm. TDS. The surfactant components comprise (a) a water-soluble alkyl- or alkylaryl-polyalkoxyalkyl sulphonate having 8-24 C atoms in the alkyl chain and contg. 1-20 alkoxy gps., and (b) a water-insoluble ethoxylated alkyl-aromatic or aliphatic cpd. having 8-24 C atoms in the alkyl or aliphatic chain and contg. 1-20 ethoxy gps. The fluids are stable at higher temps. and salinities than prior art surfactant fluids. Certain combinations of (a) and (b) give a viscous fluid.</p> |
