| 摘要 |
<p>A method for recovering largely emulsion-free oil from an underground deposit of medium or high salinity by injecting, into an injection bore-hole, a 0.1 to 30% solution or dispersion, in formation- or flood-water, of carboxymethylated oxethylates of the formula: R - (OCH2CH2)n - OCH2 - COOM, wherein R signifies a linear or branched aliphatic residue with 6 to 20 carbon atoms or an alkyl- or dialkyl-aromatic residue with 3 to 16 carbon atoms in the alkyl group, M signifies an alkali or alkaline-earth metal ion or ammonium ion, n lies between 1 and 3 and the degree of carboxymethylation between 10 and 90%, the surfactant selected being such that the phase-inversion temperature of the crude-oil/formation- or flood-water/surfactant/possible additives system lies at 0 to 10.degree.C above the temperature of the deposit. The method sharply reduces pressure gradients developing during transportation of the oil through the formation.</p> |
