# US 11,078,406 B2 · Altering wettability in subterranean formations

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- Number: US 11,078,406 B2
- Document ID: US11078406B2
- Status: Granted
- Kind: B2
- Application number: 16/395,059
- Filed: 2019-04-25
- Published: 2020-10-29
- Granted: 2021-08-03
- Earliest claimed: 2019-04-25
- Assignees: Saudi Arabian Oil Company
- Applicants: Saudi Arabian Oil Company
- Inventors: Katherine Leigh Hull; Mohammed Sayed
- Web page: https://patentgrep.com/patent/US11078406B2

## CPC

- C09K 8/601: {using spacer compositions}
- C09K 8/58: Compositions for enhanced recovery methods for obtaining hydrocarbons, i.e. for improving the mobility of the oil, e.g. displacing fluids
- C09K 8/64: Oil-based compositions
- C09K 8/665: {containing inorganic compounds (proppants C09K8/80)}
- C09K 8/70: characterised by their form or by the form of their components, e.g. foams
- C09K 8/80: Compositions for reinforcing fractures, e.g. compositions of proppants used to keep the fractures open
- E21B 43/25: Methods for stimulating production {(by vibrating earth formations E21B43/003)}
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS

## Abstract

A method of altering wettability of a subterranean formation penetrated by a well is described. A first oxidizer including a persulfate is introduced to the subterranean formation. A second oxidizer including a bromate is introduced to the subterranean formation. The well is shut in for a period of time to allow the first oxidizer and the second oxidizer to alter the wettability of the subterranean formation toward non-wetting of oil and of water.

## Claims

### Claim 1

A method of altering a wettability of a subterranean formation penetrated by a well, the method comprising:
introducing a first oxidizer comprising a persulfate to the subterranean formation;
introducing a second oxidizer comprising a bromate to the subterranean formation;
shutting in the well for a period of time to allow the first oxidizer and the second oxidizer to alter the wettability of the subterranean formation toward non-wetting of oil and of water; and
determining that the wettability of the subterranean formation has been altered toward non-wetting of oil and of water by performing a contact angle test on a rock sample obtained from the subterranean formation, wherein the contact angle test comprises:
measuring a first contact angle of a first fluid comprising water on a surface of the rock sample; and
measuring a second contact angle of a second fluid comprising a hydrocarbon on the surface of the rock sample, wherein determining that the wettability of the subterranean formation has been altered toward non-wetting of oil and of water comprises determining that the first contact angle and the second contact angle are both in a range from about 70° to about 110°.

### Claim 2 (depends on 1)

The method of claim 1, comprising mixing the first oxidizer and the second oxidizer before introduction to the subterranean formation.

### Claim 3 (depends on 1)

The method of claim 1, comprising introducing a spacer fluid to the subterranean formation after introducing the first oxidizer and before introducing the second oxidizer.

### Claim 4 (depends on 1)

The method of claim 1, comprising introducing a spacer fluid to the subterranean formation after introducing the second oxidizer and before introducing the first oxidizer.

### Claim 5 (depends on 1)

The method of claim 1, comprising:
encapsulating the first oxidizer in a polymer shell or an oil phase; and
encapsulating the second oxidizer in a polymer shell or an oil phase.

### Claim 6 (depends on 1)

The method of claim 1, comprising suspending the first oxidizer and the second oxidizer in an emulsion, and introducing the first oxidizer and the second oxidizer to the subterranean formation comprises introducing the emulsion to the subterranean formation.

### Claim 7 (depends on 6)

The method of claim 6, wherein a continuous phase of the emulsion comprises diesel, solvent, crude oil, or mineral oil.

### Claim 8 (depends on 1)

The method of claim 1, comprising fracturing the subterranean formation.

### Claim 9 (depends on 1)

The method of claim 1, comprising introducing a proppant to the subterranean formation.

### Claim 10 (depends on 9)

The method of claim 9, wherein the proppant is introduced to the subterranean formation with at least one of the first oxidizer or the second oxidizer.

### Claim 11 (depends on 10)

The method of claim 10, wherein a concentration of the proppant is at most about 10 pounds per gallon.

### Claim 12 (depends on 1)

The method of claim 1, wherein the well is shut in for at least about 30 minutes.

### Claim 13 (depends on 1)

The method of claim 1, wherein the first oxidizer is an aqueous solution of the first oxidizer, and a concentration of the persulfate in the aqueous solution of the first oxidizer is at least about 0.04 M.

### Claim 14 (depends on 1)

The method of claim 1, wherein the second oxidizer is an aqueous solution of the second oxidizer, and a concentration of the bromate in the aqueous solution of the second oxidizer is at least about 0.01 M.

### Claim 15 (depends on 14)

The method of claim 14, comprising introducing a chloride salt to the subterranean formation.

### Claim 16 (depends on 15)

The method of claim 15, wherein the chloride salt is introduced as an aqueous solution of the chloride salt to the subterranean formation with at least one of the first oxidizer or the second oxidizer, and a concentration of the chloride salt is at least 0.25 M.