Process for oil recovery from a subterranean reservoir

US4485873A · kind A · utility

Assignee

• Chemische Werke Huels, A.G. · DE

Inventors

• Dieter Balzer · Haltern, DE
• Kurt Kosswig · Marl, DE

Key dates

• Filing date: Sep 1, 1982
• Grant date: Dec 4, 1984
• Expiry date: Sep 1, 2002

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S507/936
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

A process for the recovery of extensively emulsion-free oil from a subterranean reservoir of medium or high salinity comprises forcing into an injection well a 0.1-20% (e.g., 1-20%) by weight solution or dispersion in formation water of carboxymethylated ethoxylates of the formula EQU R--(OCH.sub.2 CH.sub.2).sub.n --OCH.sub.2 --COOM, wherein PA1 R is a linear or branched aliphatic residue of 4-20 carbon atoms or an alkylaromatic or dialkylaromatic residue of 1-14 carbon atoms in the alkyl group, PA1 n is 1-30, e.g., 3-30, and PA1 M is an alkali or alkaline earth metal ion or ammonium, PA1 and the degree of carboxymethylation is between 10 and 100%, wherein the carboxymethylated oxethylate is selected so that the phase inversion temperature of the system: crude oil/formation water/tenside/optional additives, is 0.degree.-10.degree. C. above the reservoir temperature.