# US 2020/0399530 A1 · Aqueous Delayed Acid System for Well Stimulation

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- Number: US 2020/0399530 A1
- Document ID: US20200399530A1
- Status: Published application
- Kind: A1
- Application number: 16/900,000
- Filed: 2020-06-12
- Published: 2020-12-24
- Earliest claimed: 2019-06-21
- Assignees: Baker Hughes, A Ge Company, LLC
- Applicants: Baker Hughes, a GE company, LLC
- Inventors: Ahmed S. Zakaria; Sumit Bhaduri; Frances H. DeBenedictis; Paul S. Carman
- Web page: https://patentgrep.com/patent/US20200399530A1

## CPC

- C09K 8/74: combined with additives added for specific purposes
- C07C 215/40: with quaternised nitrogen atoms bound to carbon atoms of the carbon skeleton
- C07F 9/062: {Organo-phosphoranes without P-C bonds}
- C09K 8/604: {Polymeric surfactants}
- C09K 8/68: containing organic compounds
- C09K 8/885: {obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds}
- E21B 43/27: by use of eroding chemicals, e.g. acids
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07F: ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM (metal-containing porphyrins C07D487/22)
- E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS

## Abstract

The disclosure relates to an aqueous acidizing fluid. In addition to an acid, the fluid contains an organophosphorus surfactant and/or an acid retarder. The organophosphorus surfactant may be an amino phosphonate or a phosphino carboxylate. The acid retarder comprises the combination of urea or a urea derivative and a bifunctional organic compound. Suitable bifunctional organic compounds contain at least one quaternary ammonium or phosphonium and at least one alcohol as well as salts of nitrogen containing heterocyclic rings.

## Claims

### Claim 1

An acidizing composition for use in acidizing a subterranean formation comprising, as a first member, an inorganic or organic acid and, as a second member:
A. an organophosphorus surfactant selected from the group consisting of amino phosphonates and phosphino carboxylates; and/or
B. an acid retarder of (a) urea or a urea derivative and (b) a bifunctional organic compound comprising (i) at least one quaternary phosphonium or ammonium moiety and at least one —OH group; or (ii) a salt of a nitrogen containing heterocyclic ring.

### Claim 2 (depends on 1)

A method of simulating a subterranean formation penetrated by a well comprising contacting the formation with the acidizing composition of claim 1 and enhancing permeability of the formation with the acidizing composition.

### Claim 3 (depends on 2)

The method of claim 2, wherein the acidizing composition contains both the organophosphorus surfactant and the acid retarder.

### Claim 4 (depends on 2)

The method of claim 2, comprising pumping the acidizing composition into the well at a pressure sufficient to create or enhance a fracture and reacting the acid with the formation to create conductive channels.

### Claim 5 (depends on 2)

The method of claim 2, comprising pumping the acidizing composition into the well at a pressure lower than that which induces creation of a fracture and creating conductive branched flow channels within the formation.

### Claim 6 (depends on 2)

The method of claim 2, comprising at least one of the following:
(a) contacting the formation with the acidizing composition wherein the acidizing composition contains the organophosphorus surfactant and retarding the spending of the acid in the well by adsorbing onto the surface of the formation the organophosphorus surfactant;
(b) contacting the formation with the acidizing composition wherein the formation is a carbonate formation and enhancing the creation and penetration of wormholes by retarding or slowing down the spending of the acid;
(c) contacting the formation with the acidizing composition wherein the acidizing composition contains an organophosphorus surfactant, adsorbing onto the surface of the formation the organophosphorus surfactant thereby limiting bonding sites for the acid and delaying spending of the acid by the presence of the adsorbed organophosphorus surfactant on the formation surface;
(d) combining water, the first member and the second member to form the aqueous acidizing fluid, pumping the aqueous acidizing fluid into the well and delaying spending of the acid with the second member; or
(e) pumping into the acidizing fluid wherein the acidizing fluid contains the acid retarder and decreasing transfer of the acid proton onto the surface of the formation.

### Claim 7 (depends on 2)

The method of claim 2, wherein the organophosphorus surfactant is an amino phosphonate.

### Claim 8 (depends on 2)

The method of claim 2, wherein the organophosphorus surfactant has at least one
—OH group, at least one alkyl group, a phosphonium group and at least one ammonium group.

### Claim 9 (depends on 7)

The method of claim 7, wherein the organophosphorus surfactant is an amino phospholipid.

### Claim 10 (depends on 9)

The method of claim 9, wherein the phospholipid is of the structure:
wherein R and R′ are C6 to C25 hydrocarbon groups and A is selected from the group consisting of halide, nitrate, sulfate, phosphate, anions of C1 to C10 organic acids and mixtures thereof.

### Claim 11 (depends on 9)

The method of claim 9, wherein the phospholipid is selected from the group consisting of a cocadmidopropyl PG-dimonium chloride phosphate salt, a ricinoleamidopropyl PG-dimonium chloride phosphate, a dilinoleamidopropyl PG-dimonium chloride phosphate, sodium cocamidopropyl PG-dimonium chloride phosphate and sodium dilinoleamidopropyl PG-dimonium chloride phosphate, a dimer dilinoleamido-propyl PG-dimonium chloride phosphate; linoleamidopropyl PG-dimonium chloride phosphate dilinoleamidopropyl PG-dimonium chloride phosphate, a 1-propanaminium, 3,3′,3″-[phosphinylidynetris(oxy)]tris[N-(3-aminopropyl)-2-hydroxy-N,N-dimethyl-, N,N′,N″-tri-C6-18 acyl derivative trichlorides, at least one fatty acid amidopropyl propylene glycol dimonium phosphate salt wherein the fatty acid is a C10 C25 fatty acid and mixtures thereof.

### Claim 12 (depends on 2)

The method of claim 2, wherein the organophosphorus surfactant is an ester based phosphobetaine having a quaternized nitrogen.

### Claim 13 (depends on 7)

The method of claim 7, wherein the organophosphorus surfactant is an amino phosphonate of the formula (II):
wherein:
R1 is alkyl or alkylene having between 7 and 21 carbon atoms;
a, b and c are each independently integers ranging from 0 to 20, with the proviso that a+b+c be equal to or greater than 1;
R2 is selected from the group consisting of alkyl having 7 to 21 carbon atoms and
R3—C(O)—N(H)—(CH2)2— where R3 is alkyl having 7 to 21 carbon atoms.

### Claim 14 (depends on 2)

The method of claim 2, wherein the organophosphorus surfactant is an amino phosphonic acid, a phosphino carboxylate or a phosphino derivatized or partially neutralized phosphinocarboxylate polymer of approximate number average molecular weight from about 500 to 20,000 or an oil soluble blend of a tertiary alkyl amine and an amino phosphonic acid.

### Claim 15 (depends on 2)

The method of claim 2, wherein, the bifunctional organic compound is a phosphonium hydroxyl C1-C4 alkyl salt.

### Claim 16 (depends on 15)

The method of claim 15, wherein the bifunctional organic compound is a phosphonium chloride or a sulfate based compound.

### Claim 17 (depends on 15)

The method of claim 15, wherein the bifunctional organic compound is a tetrakishydroxymethyl phosphonium salt.

### Claim 18 (depends on 2)

The method of claim 2, wherein the bifunctional organic compound contains both quaternary ammonium or phosphonium and an alcohol.

### Claim 19 (depends on 18)

The method of claim 18, wherein the bifunctional organic compound is choline chloride.

### Claim 20 (depends on 2)

The method of claim 2, wherein the bifunctional organic compound is a hydroxyethyl ammonium salt.

### Claim 21 (depends on 20)

The method of claim 20, wherein the bifunctional organic compound is trimethyl hydroxyethyl ammonium chloride.

### Claim 22 (depends on 2)

The method of claim 2, wherein the bifunctional organic compounds is a salt of a nitrogen containing heterocyclic ring.

### Claim 23 (depends on 22)

The method of claim 22, wherein the bifunctional organic compound is a salt of an imidazoline.