# US 2024/0200430 A1 · Stimulating hydrocarbon reservoirs

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- Number: US 2024/0200430 A1
- Document ID: US20240200430A1
- Status: Published application
- Kind: A1
- Application number: 18/416,517
- Filed: 2024-01-18
- Published: 2024-06-20
- Earliest claimed: 2022-06-01
- Assignees: Saudi Arabian Oil Company
- Applicants: Saudi Arabian Oil Company
- Inventors: Katherine Leigh Hull; Amy J. Cairns; Rajesh Kumar Saini
- Web page: https://patentgrep.com/patent/US20240200430A1

## CPC

- E21B 43/164: {Injecting CO2 or carbonated water (in combination with organic material C09K8/594)}
- E21B 43/27: by use of eroding chemicals, e.g. acids
- C09K 8/594: Compositions used in combination with injected gas {, e.g. CO2 orcarbonated gas}(C09K8/592 takes precedence)
- C09K 8/74: combined with additives added for specific purposes
- E21B 43/25: Methods for stimulating production {(by vibrating earth formations E21B43/003)}
- E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE

## Abstract

Techniques for treating a hydrocarbon reservoir include delivering a composition to the hydrocarbon reservoir. The composition includes at least one acid, and liquid or supercritical carbon dioxide (CO2). The method further includes exposing the delivered composition to water to activate the composition; and treating a rock formation of the hydrocarbon reservoir with the activated composition.

## Claims

### Claim 1

A method for treating a hydrocarbon reservoir, comprising:
delivering a composition to the hydrocarbon reservoir, the composition comprising:
at least one acid, and
liquid or supercritical carbon dioxide (CO2);
exposing the delivered composition to water to activate the composition; and
treating a rock formation of the hydrocarbon reservoir with the activated composition.

### Claim 2 (depends on 1)

The method of claim 1, wherein the at least one acid is directly dissolved in the liquid or supercritical CO2.

### Claim 3 (depends on 2)

The method of claim 2, wherein the at least one acid is selected from the group consisting of acetic acid, formic acid, trifluoroacetic acid, propionic acid, 2-hydroxypropanoic acid, and 2-hydroxyhexanoic acid.

### Claim 4 (depends on 1)

The method of claim 1, wherein the at least one acid is dissolved in the liquid or supercritical CO2 with a cosolvent or surfactant.

### Claim 5 (depends on 4)

The method of claim 4, wherein the at least one acid is p-methylbenzene sulfonic acid, and the cosolvent or surfactant is selected from the group consisting of ethyl acetate, ethyl acetate and ethanol, ethanol, and acetone.

### Claim 6 (depends on 4)

The method of claim 4, wherein the at least one acid is benzoic acid, and the cosolvent or surfactant is selected from the group consisting of ethanol, ethanol and ethyl acetate, and ethyl acetate.

### Claim 7 (depends on 4)

The method of claim 4, wherein the at least one acid is hydroxybenzoic acid, and the cosolvent or surfactant is ethanol.

### Claim 8 (depends on 4)

The method of claim 4, wherein the at least one acid is hydrofluoric acid, and the cosolvent or surfactant is pyridine.

### Claim 9 (depends on 4)

The method of claim 4, wherein the at least one acid is methanesulfonic acid, and the cosolvent or surfactant is selected from the group consisting of ethanol, acetone, and ethyl acetate.

### Claim 10 (depends on 1)

The method of claim 1, wherein the composition comprises the at least one acid and the liquid or supercritical CO2 in an acid-CO2 emulsion with an outer continuous phase that comprises the liquid or supercritical CO2 and an internal phase that comprises the at least one acid and a surfactant.

### Claim 11 (depends on 1)

The method of claim 1, wherein the at least one acid comprises a first acid and a second acid.

### Claim 12 (depends on 11)

The method of claim 11, wherein the first acid is selected from the group consisting of hydrochloric acid (HCl), a strong mineral acid, hydrofluoric acid (HF), a sulfonic acid, ethanesulfonic acid, p-toluene sulfonic acid, formic acid, lactic acid, acetic acid, propanoic acid, 2-hydroxypropanoic acid, and 2-hydroxyhexanoic acid, and
the second acid is selected from the group consisting of acetic acid, trifluoroacetic acid, propanoic acid, formic acid, 2-hydroxypropanoic acid, and 2-hydroxyhexanoic acid.

### Claim 13 (depends on 10)

The method of claim 10, wherein the at least one acid is selected from the group consisting of hydrochloric acid (HCl), a strong mineral acid, hydrofluoric acid (HF), a sulfonic acid, ethanesulfonic acid, p-toluene sulfonic acid, formic acid, lactic acid, acetic acid, propanoic acid, 2-hydroxypropanoic acid, and 2-hydroxyhexanoic acid.

### Claim 14 (depends on 10)

The method of claim 10, wherein the surfactant comprises a fluorinated surfactant that is selected from the group consisting of ammonium carboxylic acid perfluoroether; C7F15CH(OSO3Na+)C7H15; bis(1H,1H,5H-octafluoro-n-pentyl) sodium sulfosuccinate (di-HCF4); sodium 1-oxo-1-[4-(perfluorohexyl)phenyl]hexane-2-sulfonate, FC6-HC4; 1-oxo-1-[4-(perfluorohexyl)phenyl]hexane (Nohead FC6HC4); sodium 1,5bis[(1H, 1H,2H,2H-perfluorobutyl)oxy]-1,5-dioxopentane-2-sulfonate (2FG(EO)2); sodium 1,5-bis[(1H, 1H,2H,2H-perfluorohexyl)oxy]-1,5dioxopentane-2-sulfonate (4FG(EO)2); sodium 1,5-bis[(1H, 1H,2H,2H-perfluorodecyl)oxy]-1,5-dioxopentane-2-sulfonate (8FG(EO)2); sodium 1,4-bis[(1H, 1H,2H,2H-perfluorohexyl)oxy]-1,4dioxobutane-2-sulfonate (4FS(EO)2); sodium 1,4-bis[(1H, 1H,2H,2H-perfluorodecyl)oxy]-1,4-dioxobutane-2-sulfonate (8FS(EO)2), and [C6F13mim][(CF3)3S], [C6F13mim]-[C6F13S], and [C5F11mim][C5F11S].

### Claim 15 (depends on 10)

The method of claim 10, wherein the surfactant comprises a nonfluorinated surfactant that is a poly(ethylene glycol) 2,6,8-trimethyl-4-nonyl ether.

### Claim 16 (depends on 1)

The method of claim 1, wherein the composition comprises the at least one acid and the liquid or supercritical CO2 in an acid-CO2 foam with an outer continuous phase that comprises water and an internal phase that comprises the at least one acid and the liquid or supercritical CO2.

### Claim 17 (depends on 16)

The method of claim 16, wherein the composition comprises the at least one acid and greater than 50% liquid or supercritical CO2 by volume.

### Claim 18 (depends on 16)

The method of claim 16, wherein the composition comprises less than 50% water by volume.

### Claim 19 (depends on 16)

The method of claim 16, wherein the at least one acid comprises a first acid in the internal phase and a second acid in the outer continuous phase.

### Claim 20 (depends on 19)

The method of claim 19, wherein the first acid is selected from the group consisting of acetic acid, trifluoroacetic acid, propanoic acid, formic acid, 2-hydroxypropanoic acid, and 2-hydroxyhexanoic acid, and
the second acid is selected from the group consisting of HCl, a strong mineral acid, HF, a sulfonic acid, ethanesulfonic acid, p-toluene sulfonic acid, formic acid, lactic acid, acetic acid, propanoic acid, 2-hydroxypropanoic acid, and 2-hydroxyhexanoic acid.

### Claim 21 (depends on 1)

The method of claim 1, further comprising:
delivering a pre-flush to the hydrocarbon reservoir prior to delivering the composition to the hydrocarbon reservoir; and
delivering a post-flush to the hydrocarbon reservoir subsequent to delivering the composition to the hydrocarbon reservoir.

### Claim 22 (depends on 1)

The method of claim 1, further comprising diverting the delivered composition to a particular location in the hydrocarbon reservoir.