Fluoro-inorganics for well cleaning and rejuvenation

• US 10,035,949 B2
• Filed: 08/16/2016
• Issued: 07/31/2018
• Est. Priority Date: 08/18/2015
• Status: Active Grant

• Current Assignee: Ecolab USA Incorporated (Ecolab, Inc.)
• Original Assignee: Ecolab USA Incorporated (Ecolab, Inc.)
• Inventors: Gill, Jasbir S., Sommese, Anthony G., Miller, Thomas M., Rodman, David
• Primary Examiner(s): Runyan, Silvana C
• Application Number:
  US15/238,002
• Publication Number:
  US 20170051198A1
• Time in Patent Office: 714 Days
• Field of Search: 166307
• CPC Class Codes: C09K 2208/32 Anticorrosion additives
• CPC Class Codes: C09K 8/528 inorganic depositions, e.g. sulfates or carbonates
• CPC Class Codes: C09K 8/72 Eroding chemicals, e.g. acids
• CPC Class Codes: E21B 43/27 by use of eroding chemicals, e.g. acids

Abstract

The present invention generally relates to methods for increasing recovery of crude oil from a subterranean hydrocarbon-containing formation and for removing or inhibiting deposits in a well, the methods comprising contacting an acid composition that comprises a salt of a nitrogen base having a fluoro inorganic anion with the well or the formation.

Claims

1. A method for increasing recovery of crude oil from a subterranean hydrocarbon-containing formation, the method comprising:

injecting an acid composition comprising a salt of a nitrogen base having a fluoro inorganic anion into a well which is in contact with the subterranean hydrocarbon-containing formation.

2. The method of claim 1, wherein the acid composition is diverted toward a zone of the subterranean hydrocarbon-containing formation that has a lower permeability to fluid than an adjacent zone.

3. The method of claim 2, wherein the subterranean hydrocarbon-containing formation comprises a sandstone reservoir or a carbonate reservoir.

4. The method of claim 3, wherein the subterranean hydrocarbon-containing formation comprises a carbonate reservoir.

5. The method of claim 1, wherein the acid composition further comprises a surfactant.

6. The method of claim 5, wherein the surfactant is a nonionic surfactant.

7. The method of claim 1, wherein the fluoro inorganic anion comprises a borate ion, a phosphate ion, or a combination thereof.

8. The method of claim 7, wherein the fluoro inorganic anion is tetrafluoroborate, hexafluorophosphate, or a combination thereof.

9. The method of claim 8, wherein the fluoro inorganic anion comprises tetrafluoroborate.

10. The method of claim 1, wherein the nitrogen base is urea, biuret, an alkyl urea, an alkanolamine, an alkylamine, a dialkylamine, a trialkylamine, an alkyldiamine, an alkyltriamine, an alkyltetramine, a polyamine, an acrylamide, a polyacrylamide, a vinyl pyrollidone, a polyvinyl pyrollidone, or a combination thereof.

11. The method of claim 10, wherein the nitrogen base comprises urea.

12. The method of claim 1, wherein the fluoro inorganic anion comprises tetrafluoroborate and the nitrogen base comprises urea and the molar ratio of urea to tetrafluroboric acid used to prepare the salt is 1:

3 to 3;

1.

13. The method of claim 12, wherein the concentration of the acid composition is from about 5 wt. % to about 30 wt. % based on the total weight of the aqueous mixture injected.

14. A method for increasing recovery of a geothermal fluid from a subterranean geothermal fluid-containing formation, the method comprising:

injecting an acid composition comprising a salt of a nitrogen base having a fluoro inorganic anion into a well which is in contact with the subterranean geothermal fluid-containing formation.

15. The method of claim 14, wherein the acid composition is diverted toward a zone of the subterranean geothermal fluid-containing formation that has a lower permeability to fluid than an adjacent zone.

16. The method of claim 15, wherein the subterranean geothermal fluid-containing formation comprises a sandstone reservoir or a carbonate reservoir.

17. The method of claim 16, wherein the subterranean geothermal fluid-containing formation comprises a carbonate reservoir.

18. A method for removing an inorganic or organic deposit by contacting an acid composition with an internal surface of a well, the surface being in contact with a liquid containing deposit-forming species,

wherein the acid solution comprises a salt of a nitrogen base having a fluoro inorganic anion.

19. The method of claim 18, wherein the well is an oil well, a geothermal well, a disposal well, or a reinjection well.

20. The method of claim 18, wherein the deposit is a metal oxalate, a metal carbonate, a silicate, a metal sulfate, or a combination thereof.