Use of a borate-acid buffer in oil and gas operations

Patent metadata

Field	Value
Publication number	US-12331245-B2
Application number	US-202318488079-A
Country	US
Kind code	B2
Filing date	Oct 17, 2023
Priority date	Jul 31, 2018
Publication date	Jun 17, 2025
Grant date	Jun 17, 2025

Abstract

Provided herein are compositions comprising borate-acid buffers, as well as methods of using these compositions in oil and gas operations, including enhanced oil recovery (EOR) operations, fracturing operations, stimulation operations, etc.

First claim

What is claimed is:

1. An aqueous composition comprising (i) a borate-acid buffer, (ii) a surfactant package, (iii) water, and (iv) a water-soluble polymer,
wherein the borate-acid buffer exhibits a capacity to buffer at a pH of from 6.0 to 8.5; and
wherein the aqueous composition has a viscosity of from 0.3 mPas to 1000 mPas at 20° C.

2. The composition of claim 1 , wherein the borate-acid buffer exhibits a capacity to buffer at a pH of from 6.0 to 8.0.

3. The composition of claim 1 , wherein the borate-acid buffer exhibits a capacity to buffer at a pH of from 6.0 to less than 7.0.

4. The composition of claim 1 , wherein the borate-acid buffer comprises a borate compound and a conjugate base of an acid.

5. The composition of claim 4 , wherein the borate compound comprises sodium tetraborate, calcium tetraborate, sodium borate, sodium metaborate, or any combination thereof.

6. The composition of claim 4 , wherein the conjugate base comprises acetate, citrate, tartrate, succinate, or any combination thereof.

7. The composition of claim 4 , wherein the borate compound and the conjugate base of the acid are present at a weight ratio of from 1:1 to 5:1.

8. The composition of claim 1 , wherein the borate-acid buffer comprises a boric acid and an alkali.

9. The composition of claim 8 , wherein the alkali comprises an acetate salt, a citrate salt, a tartrate salt, a hydroxide salt, a succinate salt, or any combination thereof.

10. The composition of claim 1 , wherein the water comprises hard water or hard brine.

11. The composition of claim 1 , wherein the water comprises at least 10 ppm of divalent metal ions chosen from Ca 2+ , Mg 2+ , Sr 2+ , Ba 2+ , and combinations thereof.

12. The composition of claim 1 , wherein the surfactant package comprises a primary surfactant and optionally one or more secondary surfactants.

13. The composition of claim 12 , wherein the primary surfactant comprises an anionic surfactant selected from a sulfonate, a disulfonate, a sulfate, a disulfate, a sulfosuccinate, a disulfosuccinate, a carboxylate, a dicarboxylate, or any combination thereof.

14. The composition of claim 13 , wherein the anionic surfactant comprises one of the following:
a branched or unbranched C6-C32:PO(0-65):EO(0-100)-carboxylate;
a C10-C30 internal olefin sulfonate;
a C8-C30 alkyl benzene sulfonate (ABS); a sulfosuccinate surfactant;
a surfactant defined by the formula below
R 1 —R 2 —R 3

wherein R 1 comprises a branched or unbranched, saturated or unsaturated, cyclic or non-cyclic, hydrophobic carbon chain having 6-32 carbon atoms and an oxygen atom linking R 1 and R 2 ;
R 2 comprises an alkoxylated chain comprising at least one oxide group selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide, and combinations thereof; and
R 3 comprises a branched or unbranched hydrocarbon chain comprising 2-12 carbon atoms and from 2 to 5 carboxylate groups; or
a surfactant defined by the formula below

wherein R 4 is, individually for each occurrence, a branched or unbranched, saturated or unsaturated, cyclic or non-cyclic, hydrophobic carbon chain having 6-32 carbon atoms; and
M represents a counterion.

15. The composition of claim 12 , wherein the primary surfactant comprises a non-ionic surfactant.

16. The composition of claim 12 , wherein the primary surfactant has a concentration within the aqueous composition of from 0.05% to 5% by weight, based on the total weight of the aqueous composition.

17. The composition of claim 12 , wherein the one or more secondary surfactants comprise an anionic surfactant, a non-ionic surfactant, a cationic surfactant, a zwitterionic surfactant, or any combination thereof.

18. The composition of claim 1 , wherein the aqueous composition comprises a water-soluble polymer.

19. The composition of claim 1 , wherein the aqueous composition further comprises one or more co-solvents.

20. The composition of claim 1 , wherein the aqueous composition further comprises a polymer, a friction reducer, a gelling agent, a crosslinker, a breaker, a pH adjusting agent, a non-emulsifier agent, an iron control agent, a corrosion inhibitor, a scale inhibitor, a biocide, a clay stabilizing agent, a chelating agent, a proppant, a wettability alteration chemical, or any combination thereof.

21. The composition of claim 1 , wherein the aqueous composition has a viscosity of from 0.3 mPas to 100 mPas at 20° C.

Assignees

• Chevron Usa Inc

Inventors

• Nizamidin Nabijan
• Pinnawala Gayani W
• Tang Guo-Qing
• Dwarakanath Varadarajan
• Winslow Gregory A
• Isbell Jordan Taylor
• Malik Taimur

Classifications

• E21B47/11

  using tracers; using radioactivity · CPC title

• E21B43/26

  by forming crevices or fractures · CPC title

• E21B43/20

  Displacing by water · CPC title

• C09K8/80

  Compositions for reinforcing fractures, e.g. compositions of proppants used to keep the fractures open · CPC title

• C09K8/68

  containing organic compounds · CPC title