Process for extracting oil from a subterranean reservoir

US4478281A · kind A · utility

Assignee

• Chemische Werke Huels, A.G. · DE

Inventors

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

Key dates

• Filing date: Sep 9, 1981
• Grant date: Oct 23, 1984
• Expiry date: Sep 9, 2001

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 recovering extensively emulsion-free oil from a subterranean deposit of medium or high salinity comprises forcing into an injection well a 1-20% strength solution or dispersion in formation water of a carboxymethylated ethoxylate tenside 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 a mono- or dialkylaromatic residue of 1-14 carbon atoms in the alkyl group, PA1 n is 3-30, and PA1 M is an alkali or alkaline earth metal ion or ammonium, and wherein the degree of carboxymethylation is incomplete, wherein the tenside is selected so that the phase inversion temperature of the system: crude oil/formation water/tenside/optional additives, lies 0.degree.-10.degree. C. above the deposit temperature.