Nonionic Surfactants Employed with Extended Chain as the Oil Displacement Agent to use in Enhanced Oil Recovery

Patent metadata

Field	Value
Publication number	US-2021292636-A1
Application number	US-202016903777-A
Country	US
Kind code	A1
Filing date	Jun 17, 2020
Priority date	Mar 20, 2020
Publication date	Sep 23, 2021
Grant date	—

Abstract

Some reservoirs have tight oil formations, such as the Changqing reservoir. The surfactant polymer flooding and low tension gas flooding are two potential chemical flooding methods for use in tight oil formations. In these methods, an oil displacement agent, or surfactant, is added. Nonionic surfactants with extended chains (by propylene oxide and ethylene oxide) from dialkyl alcohols or dialkyl amines were tested. A synergistic blend of surfactants was developed between the nonionic surfactants and anionic surfactants that lowers interfacial tension and improves surfactant solubility in water and oil.

First claim

What is claimed is:

1 . A nonionic long chain surfactant of formula
C n+1 H 2n+3 CH(C n+3 H 2n+7 )CH 2 O(PO) x (EO) y H wherein: n is 3, 5, 7, 9, 11, or 13; x is from 5-50; and y is from 5-30.

2 . The nonionic long chain surfactant of claim 1 wherein the surfactant is dissolved in formation water with at least one anionic surfactant.

3 . The nonionic long chain surfactant of claim 2 wherein the at least one anionic surfactant is alkyl benzene sulfonate.

4 . The nonionic long chain surfactant of claim 2 wherein the weight ratio of the nonionic long chain surfactant to the anionic surfactant is from 2:5 to 6:1.

5 . A nonionic long chain surfactant of formula
(R) 2 N(PO) x (EO) y H wherein: R is a coco or tallow fatty alkyl chain; x is from 5-50; and y is from 5-30.

6 . The nonionic long chain surfactant of claim 5 wherein the surfactant is dissolved in formation water.

7 . The nonionic long chain surfactant of claim 6 further comprising a 0-20% salt solution.

8 . The nonionic long chain surfactant of claim 7 wherein the salt is monovalent or divalent.

9 . The nonionic long chain surfactant of claim 8 wherein the salt is selected from the group comprising: NaCl, KCl, MgCl 2 , MgCO 3 , CaCl 2 and combinations thereof.

10 . The nonionic long chain surfactant of claim 9 wherein the surfactant is also dissolved in 0-5% polymer.

11 . The nonionic long chain surfactant of claim 10 wherein the polymer is polyacrylamide.

12 . A method of preparing a nonionic long chain surfactant comprising
adding KOH to an alcohol in a reactor to form a mixture; heating the mixture in the reactor to about 100° C. with agitation under vacuum with a nitrogen purge for about 0-2 hours; heating the mixture to about 120° C.-150° C.; adding propylene oxide slowly; incubating the reaction for about 2-6 hours; adding ethylene oxide slowly; incubating the reaction for about 2-6 hours at a temperature of 100° C.-150° C.; cooling the reaction mixture to about 60° C.; and unloading the nonionic long chain surfactant.

13 . A method of enhancing oil recovery using the nonionic long chain surfactant of claim 1 comprising
dissolving the nonionic long chain surfactant in formation water to form a mixture with at least one anionic surfactant; and
flooding the reservoir with the mixture.

14 . The method of claim 13 wherein the mixture further comprises a 0-20% salt solution.

15 . The method of claim 14 wherein the salt is monovalent or divalent.

16 . The method of claim 15 wherein the salt is selected from the group comprising: NaCl, KCl, MgCl 2 , MgCO 3 , CaCl 2 , and combinations thereof.

17 . The method of claim 13 wherein the mixture further comprises a 0-5% polymer or 40-90% foam quality gases with 0-1% foamer.

18 . The method of claim 17 wherein the polymer is polyacrylamide.

19 . The method of claim 17 wherein the foamer is cocoamidopropyl betaine.

20 . The method of claim 17 wherein the foam quality gases are at least one selected from the group consisting of nitrogen, de-oxygenated air, and natural gas.

Assignees

• Cnpc Usa Corp
• Beijing Huamei Incorporated Cboc
• Beijing Huamei Incorporated Cnpc

Inventors

• Zhou Nancy Chun
• Liu Fuchen

Classifications

• C09K8/588

  characterised by the use of specific polymers {(polymeric surfactants C09K8/584)} · CPC title

• C09K8/602

  containing surfactants · CPC title

• C09K8/594

  Compositions used in combination with injected gas {, e.g. CO2 orcarbonated gas}(C09K8/592 takes precedence) · CPC title

• C09K8/584 Primary

  characterised by the use of specific surfactants · CPC title

• E21B43/20

  Displacing by water · CPC title