US 4,077,471 AGranted

Surfactant oil recovery process usable in high temperature, high salinity formations

AssigneeTexaco Inc.

InventorsRussell D. Shupe, Jim Maddox, Jr.

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Abstract

Many petroleum formations contain water having high salinity and/or high concentrations of divalent ions such as calcium or magnesium dissolved therein, and are additionally at temperature from about 70.degree. F. to about 300.degree. F. Most surfactants suitable for use in oil recovery operations are either ineffective in high salinity or high hardness waters, or cannot tolerate the higher temperatures encountered in many such formations. An aqueous fluid containing a water soluble alkylpolyalkoxyalkyl sulfonate or alkylarylpolyalkoxyalkyl sulfonate and a water-insoluble polyethoxylated aliphatic alcohol or polyethoxylated alkylphenol nonionic surfactant is effective in formations containing water whose salinity is from 70,000 to 220,000 parts per million total dissolved solids and also having temperatures as high as 300.degree. F. The fluid is phase stable over a wide range of formation temperatures and water salinities and hardness values.

Claims19

Dependent claims

A method for recovering petroleum from a subterranean, permeable, petroleum-containing formation penetrated by at least one injection well and by at least one spaced apart production well, both wells being in fluid communication with the formation, the temperature of the formation being from about 70.degree. F to about 300.degree. F., said formation containing water having a salinity from 70,000 to 220,000 parts per million total dissolved solids, comprising:

(1) injecting into the formation via the injection well an aqueous, saline, phase-stable surfactantcontaining fluid comprising:
(a) a water soluble alkylpolyalkoxyalkyl sulfonate or alkylarylpolyalkoxyalkyl sulfonate having from 8 to 24 carbon atoms in the alkyl chain and from 1 to 20 alkoxy groups;
(b) a water insoluble nonionic surfactant comprising an ethoxylated alkyaryl or an ethoxylated aliphatic compound having from 8 to 24 carbon atoms in the alkyl or aliphatic chain and containing from 1 to 20 ethoxy groups;
(c) said surfactant fluid having a salinity from about 70,000 to about 220,000 parts per million total dissolved solids, said surfactant fluid displacing oil toward the production well;
and
(2) recovering petroleum displaced by the surfactant fluid from the formation via the production well.

3 more elements

Dependencies are inferred from the claim text.