# US 10,767,099 B2 · Compositions and methods for sealing off flow channels in contact with wet cement

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- Number: US 10,767,099 B2
- Document ID: US10767099B2
- Status: Granted
- Kind: B2
- Application number: 16/510,779
- Filed: 2019-07-12
- Published: 2019-11-07
- Granted: 2020-09-08
- Earliest claimed: 2016-11-04
- Assignees: Saudi Arabian Oil Company
- Applicants: Saudi Arabian Oil Company
- Inventors: B. Raghava Reddy; Matthew Hilfiger
- Web page: https://patentgrep.com/patent/US10767099B2

## CPC

- C09K 8/44: containing organic binders only
- C08F 222/02: Acids; Metal salts or ammonium salts thereof {, e.g. maleic acid or itaconic acid}
- C08F 222/06: Maleic anhydride
- C08F 224/00: Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a heterocyclic ring containing oxygen (cyclic esters of polyfunctional acids C08F218/00; cyclic anhydrides of unsaturated acids C08F220/00, C08F222/00)
- C08K 3/26: Carbonates; Bicarbonates
- C08K 3/32: Phosphorus-containing compounds
- C08K 3/38: Boron-containing compounds
- C08K 5/0025: {Crosslinking or vulcanising agents; including accelerators}
- C09K 8/428: {for squeeze cementing, e.g. for repairing}
- C09K 8/512: containing cross-linking agents
- E21B 33/14: for cementing casings into boreholes
- C08K 5/17: Amines; Quaternary ammonium compounds
- C08K 2003/262: {Alkali metal carbonates}
- C08K 2003/321: {Phosphates}
- C08K 2003/387: {Borates}
- C08L 2201/54: Aqueous solutions or dispersions
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)

## Abstract

Treating a subterranean formation with a composition including a maleic anhydride copolymer, an amine crosslinker, and a gelling agent. The maleic anhydride copolymer includes first repeat units I and II and at least one of second repeat units III and IV: where each R1 is independently-H, —O(C1-C5) alkyl, or —(C1-C5) alkyl; each R2 is independently-H, —O(C1-C5) alkyl, or —(C1-C5) alkyl; each R3 is independently —OH or —O−M1, each M1 is independently an alkali metal, an alkaline earth metal, an ammonium ion, or a quaternary ammonium ion; and each R4 is independently-NH2 or —OM1. The gelling agent includes at least one of: a calcium chelating agent, a calcium precipitating agent, a pH buffer, an agent reactive with hydroxide, and an acid generating agent, and promotes formation of a gel from the maleic anhydride copolymer and the amine crosslinker in contact with set cement.

## Claims

### Claim 1

A composition for treating a subterranean formation, the composition comprising:
a maleic anhydride copolymer comprising first repeat units I and II:
wherein each R1 is independently selected from the group consisting of —H, —O(C1-C5) alkyl, and —(C1-C5) alkyl, and each R2 is independently selected from the group consisting of —H, —O(C1-C5) alkyl, and —(C1-C5) alkyl;
an amine crosslinker;
a gelling agent comprising at least one of:
a calcium chelating agent;
a calcium precipitating agent;
a pH buffer;
an agent reactive with hydroxide; or
an acid generating agent,
wherein the gelling agent promotes formation of a gel from the maleic anhydride copolymer and the amine crosslinker in contact with set cement.

### Claim 2 (depends on 1)

The composition of claim 1, wherein the maleic anhydride copolymer comprises at least one second repeat unit selected from the group consisting of repeat units III and IV:
wherein each R3 is independently selected from the group consisting of —OH and —O−M1, each M1 is independently selected from the group consisting of an alkali metal, an alkaline earth metal, an ammonium ion, and a quaternary ammonium ion, and each R4 is independently selected from the group consisting of —NH2 and —OM1.

### Claim 3 (depends on 2)

The composition of claim 2, wherein repeat unit III and repeat unit IV comprise repeat unit IIIA and repeat unit IVA, respectively:

### Claim 4 (depends on 1)

The composition of claim 1, wherein the gelling agent comprises a salt of a weak acid and a base.

### Claim 5 (depends on 4)

The composition of claim 4, wherein the base comprises an organic base.

### Claim 6 (depends on 4)

The composition of claim 4, wherein the base comprises an inorganic base.

### Claim 7 (depends on 4)

The composition of claim 4, wherein the base is a strong base or a weak base.

### Claim 8 (depends on 1)

The composition of claim 1, wherein the gelling agent comprises sodium hexametaphosphate, sodium tetraborate, disodium hydrogen phosphate, sodium carbonate, or sodium phosphate.

### Claim 9 (depends on 1)

The composition of claim 1, wherein the gelling agent comprises pentasodium salt of amino tris(methylene phosphonic acid).

### Claim 10 (depends on 1)

The composition of claim 1, wherein the gelling agent comprises a buffer solution of a weak acid and an organic base.

### Claim 11 (depends on 1)

The composition of claim 1, wherein the gelling agent comprises a buffer solution of ethanolamine and citric acid.

### Claim 12 (depends on 1)

The composition of claim 1, wherein the gelling agent is about 0.5% to about 10% of the composition by weight, and wherein pH of the composition is in a range of about 3 to about 10.

### Claim 13 (depends on 1)

The composition of claim 1, wherein the gelling agent promotes formation of the gel comprising the maleic anhydride copolymer and the amine crosslinker in contact with set cement at a temperature in a range of about 100° F. to 180° F.

### Claim 14 (depends on 1)

The composition of claim 1, wherein the gelling agent promotes formation of the gel from the maleic anhydride copolymer and the amine crosslinker in contact with set cement in about 8 hours or less.

### Claim 15

A method of treating a subterranean formation, the method comprising:
providing to the subterranean formation a composition comprising:
a maleic anhydride copolymer comprising:
first repeat units I and II:
wherein each R1 is independently selected from the group consisting of —H, —O(C1-C5) alkyl, and —(C1-C5) alkyl, and each R2 is independently selected from the group consisting of —H, —O(C1-C5) alkyl, and —(C1-C5) alkyl;
an amine crosslinker; and
a gelling agent comprising at least one of:
a calcium chelating agent;
a calcium precipitating agent;
a pH buffer;
an agent reactive with hydroxide; or
an acid generating agent; and
crosslinking the maleic anhydride copolymer of the composition with the amine crosslinker of the composition to form a sealant, wherein the gelling agent promotes formation of the sealant in contact with set cement.

### Claim 16 (depends on 15)

The method of claim 15, wherein the maleic anhydride copolymer comprises at least one second repeat unit selected from the group consisting of repeat units III and IV:
wherein each R3 is independently selected from the group consisting of —OH and —O−M1, each M1 is independently selected from the group consisting of an alkali metal, an alkaline earth metal, an ammonium ion, and a quaternary ammonium ion, and each R4 is independently selected from the group consisting of —NH2 and —OM1.

### Claim 17 (depends on 15)

The method of claim 15, wherein crosslinking the composition to form the sealant occurs near a casing, a casing-casing annulus, a tubing-casing annulus, or a casing-formation annulus.

### Claim 18 (depends on 15)

The method of claim 15, wherein crosslinking the composition to form the sealant prevents or retards undesired loss or flow of wellbore fluid into the formation or of formation fluids into the wellbore.

### Claim 19

A method of treating a subterranean formation, the method comprising:
providing, to the subterranean formation comprising a cemented zone comprising set cement, an aqueous solution comprising a gelling agent to yield a pretreated subterranean formation, wherein gelling agent comprises at least one of:
a calcium chelating agent;
a calcium precipitating agent;
a pH buffer;
an agent reactive with hydroxide; or
an acid generating agent;
providing to the pretreated subterranean formation a composition comprising:
a maleic anhydride copolymer comprising first repeat units I and II:
wherein each R1 is independently selected from the group consisting of —H, —O(C1-C5) alkyl, and —(C1-C5) alkyl, and each R2 is independently selected from the group consisting of —H, —O(C1-C5) alkyl, and —(C1-C5) alkyl; and
an amine crosslinker; and
crosslinking the maleic anhydride copolymer of the composition with the amine crosslinker of the composition to form a sealant, wherein the gelling agent promotes formation of the sealant in contact with set cement.

### Claim 20 (depends on 19)

The method of claim 19, wherein the maleic anhydride copolymer comprises at least one second repeat unit selected from the group consisting of repeat units III and IV:
wherein each R3 is independently selected from the group consisting of —OH and —O−M1, each M1 is independently selected from the group consisting of an alkali metal, an alkaline earth metal, an ammonium ion, and a quaternary ammonium ion, and each R4 is independently selected from the group consisting of —NH2 and —OM1.

### Claim 21 (depends on 19)

The method of claim 19, wherein the gelling agent is a first gelling agent, and the composition comprises a second gelling agent.