# US 8,273,693 B2 · Polymeric gel system and methods for making and using same in hydrocarbon recovery

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- Number: US 8,273,693 B2
- Document ID: US8273693B2
- Status: Granted
- Kind: B2
- Application number: 11/760,581
- Filed: 2007-06-08
- Published: 2008-10-16
- Granted: 2012-09-25
- Earliest claimed: 2001-12-12
- Assignees: Clearwater International, LLC
- Inventors: Kevin M. Schwartz
- Web page: https://patentgrep.com/patent/US8273693B2

## CPC

- C09K 8/12: containing synthetic organic macromolecular compounds or their precursors
- B08B 9/0555: {Gelled or degradable pigs}
- C09K 8/24: Polymers
- C09K 8/38: Gaseous or foamed well-drilling compositions
- C09K 8/40: Spacer compositions, e.g. compositions used to separate well-drilling from cementing masses
- C09K 8/602: {containing surfactants}
- C09K 8/665: {containing inorganic compounds (proppants C09K8/80)}
- C09K 8/68: containing organic compounds
- C09K 8/703: {Foams}
- C09K 8/882: {obtained by reactions only involving carbon-to-carbon unsaturated bonds}
- E21B 17/1064: {Pipes or rods with a relatively rotating sleeve}
- F17D 3/08: the different products being separated by "go-devils", e.g. spheres (cleaning devices moved along inside a pipe-lines by fluid pressure B08B9/04; {pigs or moles per se, their launching and detection F16L55/26})
- C09K 2208/26: Gel breakers other than bacteria or enzymes
- C09K 2208/28: Friction or drag reducing additives
- C09K 2208/30: Viscoelastic surfactants [VES]
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- B08B: CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- F17D: PIPE-LINE SYSTEMS; PIPE-LINES (pumps or compressors F04; fluid dynamics F15D; valves or the like F16K; pipes, laying pipes, supports, joints, branches, repairing, work on the entire line, accessories F16L; steam traps or the like F16T; fluid-pressure electric cables H01B9/06)

## Abstract

Coacervate gels having excellent shear viscosities and other properties are made with anionic or cationic polymers, a smaller amount of a surfactant having a charge opposite that of the polymer, and a hydrophobic alcohol and an effective amount of a phosphorus-containing compound sufficient to increase the viscosity of coacervate gels up to 3 times as compared to the gels in the absence of the phosphorus-containing compound. The Zeta Potential of the gel is maintained at an absolute value of at least 20. Optional gel promoting additives include betaines and amine oxides. A preferred gel comprises poly diallyl dimethyl ammonium chloride, a lesser amount of sodium lauryl sulfonate, and lauryl alcohol. The gels are particularly useful in well drilling fluids and well fracturing fluids.

## Claims

### Claim 1

An aqueous gel comprising:
water and, by weight based on the water,
0.1% to 5% of an anionically or cationically charged polymer,
a lesser amount but at least 0.01% of an oppositely charged surfactant having from 8 to 22 carbon atoms,
from 0.001 to 5% of a hydrophobic alcohol,
from about 0.001% and about 10% of a phosphorus-containing compound comprising mono carbyl phosphates, di carbyl phosphates, tri carbyl phosphates, phosphate salts or mixtures and combinations thereof,
up to 5% of an amphoteric surfactant, and
up to 5% of an amine oxide,
where the gel has an absolute value of a Zeta Potential of at least 20 millivolts and where the phosphorus-containing compound increases a viscosity of the gel as much as 3 times relative to a viscosity of a gel without the phosphorus-containing compound, and where the aqueous gel is useful in drilling, formation fracturing, and hydrocarbon recovery.

### Claim 2 (depends on 1)

The gel of claim 1, wherein the polymer is an anionic polymer comprising at least 20% mer units derived from 2-acrylamido-2-methylpropane sulfonic acid.

### Claim 3 (depends on 1)

The gel of claim 1, wherein the amphoteric surfactant comprises a betaine or sultaine gel promoter and is present in an amount from 0.001% to 2%.

### Claim 4 (depends on 1)

The gel of claim 1, wherein the amphoteric surfactant comprises cocamidopropyl betaine and is present in an amount from 0.001% to 2%.

### Claim 5 (depends on 1)

The gel of claim 1, wherein the amine oxide comprises lauryl amine oxide and is present in an amount from 0.001% to 2%.

### Claim 6 (depends on 1)

The gel of claim 1, wherein the polymer is a cationic polymer and the hydrophobic alcohol is a linear or branched alkyl alcohol of the general formula CMH2M+2−N(OH)N, where M is a number from 6-23, and N is 1 when M is 6-12, but where M is 13-23, N may be a number from 1 to 3, the gel including at least one of (a) 0.001% to 5% amine oxide and (b) 0.001% amphoteric surfactant.

### Claim 7 (depends on 1)

The gel of claim 1, wherein the alkyl alcohol is a linear monohydric alcohol having from 8-15 carbon atoms.

### Claim 8 (depends on 7)

The gel of claim 7, wherein the alkyl alcohol comprises lauryl alcohol.

### Claim 9 (depends on 1)

The gel of claim 1, wherein the phosphorus-containing compound comprises a phosphate, a phosphate equivalent or mixtures or combinations thereof and wherein the effective amount of the phosphorus-containing compound is between about 1% and about 6%.

### Claim 10 (depends on 9)

The gel of claim 9, wherein the phosphate is selected from the group consisting of mono-alkali metal phosphates (PO(OH)(OM), where M is Li, Na, K, Rd, or Cs, di-alkali metal phosphates (PO(OH)(OM)2, where each M is the same or different and is Li, Na, K, Rd, or Cs, tri-alkali metal phosphates (PO(OM)3, where each M is the same or different and is Li, Na, K, Rd, or Cs, carbyl phosphates (PO(OR1)(OM)2, where R1 is a carbyl group and M is H, Li, Na, K, Rd, and/or Cs, dicarbyl phosphates (PO(OR1)(OR2)(OM), where R1 and R2 are the same or different carbyl groups and M is H, Li, Na, K, Rd, or Cs, tricarbyl phosphates (PO(OR1)(OR2)(OR3), where R1, R2, and R3 are the same or different carbyl groups), and mixtures or combinations thereof.

### Claim 11 (depends on 10)

The gel of claim 10, wherein R1, R2, and R3 are carbyl groups having between about 3 and 40 carbon atoms, where one or more of the carbon atoms can be replaced with a hetero atom selected from the group consisting of oxygen and nitrogen, with the remainder of valences comprising hydrogen or a mono-valent group including a halogen, an amide (—NHCOR), or an alkoxide (—OR), where R is a carbyl group.

### Claim 12 (depends on 11)

The gel of claim 11, wherein the carbyl groups are the same or different and are selected from the group consisting of an alkyl group, an alkenyl group, an aryl group, an alkaaryl group, an aryalkyl group, or mixtures or combinations thereof.

### Claim 13 (depends on 12)

The gel of claim 12, wherein each carbyl group has between about 3 and about 20, where one or more of the carbon atoms can be replaced with a hetero atom selected from the group consisting of oxygen and nitrogen, with the remainder of valences comprising hydrogen or a mono-valent group including a halogen, or an amide (—NHCOR), an alkoxide (—OR), where R is a carbyl group.

### Claim 14 (depends on 13)

The gel of claim 13, wherein each carbyl group has between about 3 and about 16, where one or more of the carbon atoms can be replaced with a hetero atom selected from the group consisting of oxygen and nitrogen, with the remainder of valences comprising hydrogen or a mono-valent group including a halogen, an amide (—NHCOR), or an alkoxide (—OR), where R is a carbyl group.

### Claim 15 (depends on 13)

The gel of claim 13, wherein each carbyl group has between about 3 and about 12, where one or more of the carbon atoms can be replaced with a hetero atom selected from the group consisting of oxygen and nitrogen, with the remainder of valences comprising hydrogen or a mono-valent group including a halogen, an amide (—NHCOR), or an alkoxide (—OR), where R is a carbyl group.

### Claim 16 (depends on 13)

The gel of claim 13, wherein each carbyl group has between about 4 and about 8, where one or more of the carbon atoms can be replaced with a hetero atom selected from the group consisting of oxygen and nitrogen, with the remainder of valences comprising hydrogen or a mono-valent group including a halogen, an amide (—NHCOR), or an alkoxide (—OR), where R is a carbyl group.

### Claim 17 (depends on 10)

The gel of claim 10, wherein R1, R2, and R3 are alkyl groups having from about 3 to about 20 carbon atoms, where one or more of the carbon atoms can be replaced with a hetero atom selected from the group consisting of oxygen and nitrogen, with the remainder of valences comprising hydrogen or a mono-valent group including a halogen, an amide (—NHCOR), or an alkoxide (—OR), where R is a carbyl group.

### Claim 18 (depends on 10)

The gel of claim 10, wherein R1, R2, and R3 are alkyl groups having from about 4 to about 12 carbon atoms, where one or more of the carbon atoms can be replaced with a hetero atom selected from the group consisting of oxygen and nitrogen, with the remainder of valences comprising hydrogen or a mono-valent group including a halogen, an amide (—NHCOR), or an alkoxide (—OR), where R is a carbyl group.

### Claim 19 (depends on 10)

The gel of claim 10, wherein R1, R2, and R3 are alkyl groups having 4 to about 8 carbon atoms, where one or more of the carbon atoms can be replaced with a hetero atom selected from the group consisting of oxygen and nitrogen, with the remainder of valences comprising hydrogen or a mono-valent group including a halogen, an amide (—NHCOR), or an alkoxide (—OR), where R is a carbyl group.

### Claim 20 (depends on 6)

The gel of claim 6, wherein at least 20% of the mer units of the cationic polymer are derived from dimethyl diallyl ammonium chloride.

### Claim 21 (depends on 20)

A subterranean fracturing fluid comprising an aqueous gel of claim 20 and a propping agent.

### Claim 22 (depends on 20)

A subterranean drilling fluid comprising an aqueous gel of claim 20 and a foam generating gas.

### Claim 23 (depends on 20)

A subterranean formation treatment fluid comprising an aqueous gel of claim 20 and a gel breaker.

### Claim 24

A method of making an aqueous gel comprising the step of:
adding to water 0.1% to 5%, by weight based on the water, of a cationic polymer and a lesser amount but at least 0.01% by weight of an anionic surfactant having from 8 to 22 carbon atoms and from about 0.001% and about 10% of a phosphorus-containing compound comprising mono carbyl phosphates, di carbyl phosphates, tri carbyl phosphates, phosphate salts or mixtures and combinations thereof, in the presence of 0.001% to 5% linear or branched alkyl alcohol of the general formula CMH2M+2−N(OH)N, where M is a number from 6-23, and N is 1 when M is 6-12, but when M is 13-23, N may be a number from 1 to 3, and optionally in the presence of at least one of (a) up to 5% by weight amphoteric surfactant and (b) up to 5% by weight amine oxide, the ratio of the cationic polymer to the anionic surfactant being effective to provide an absolute value of a Zeta Potential of at least 20 millivolts and where the phosphorus-containing compound increases the viscosity of the gel as much as 3 times relative to a viscosity of a gel without the phosphorus-containing compound, and where the aqueous gel are useful in drilling, formation fracturing, and hydrocarbon recovery.

### Claim 25 (depends on 24)

The method of claim 24, wherein the cationic polymer comprises a polymer including mer units derived from dimethyl diallyl ammonium chloride.

### Claim 26 (depends on 24)

The method of claim 24, wherein the anionic surfactant comprises sodium lauryl sulfonate.

### Claim 27 (depends on 24)

The method of claim 24, wherein the alkyl alcohol comprises a linear monohydroxy alcohol having from 8 to 14 carbon atoms.

### Claim 28 (depends on 24)

The method of claim 24, wherein the phosphorus-containing compounds comprises a phosphate, a phosphate equivalent or mixtures or combinations thereof and wherein the effective amount of the phosphorus-containing compound is between about 0.001% and about 10%.

### Claim 29 (depends on 28)

The method of claim 28, wherein the phosphate is selected from the group consisting of mono-alkali metal phosphates (PO(OH)(OM), where M is Li, Na, K, Rd, or Cs, di-alkali metal phosphates (PO(OH)(OM)2, where each M is the same or different and is Li, Na, K, Rd, or Cs, tri-alkali metal phosphates (PO(OM)3, where each M is the same or different and is Li, Na, K, Rd, or Cs, carbyl phosphates (PO(OR1)(OM)2, where R1 is a carbyl group and M is H, Li, Na, K, Rd, and/or Cs, dicarbyl phosphates (PO(OR1)(OR2)(OM), where R1 and R2 are the same or different carbyl groups and M is H, Li, Na, K, Rd, or Cs, tricarbyl phosphates (PO(OR1)(OR2)(OR3), where R1, R2, and R3 are the same or different carbyl groups), and mixtures or combinations thereof.

### Claim 30 (depends on 29)

The method of claim 29, wherein R1, R2, and R3 are carbyl groups having between about 3 and 40 carbon atoms, where one or more of the carbon atoms can be replaced with a hetero atom selected from the group consisting of oxygen and nitrogen, with the remainder of valences comprising hydrogen or a mono-valent group including a halogen, an amide (—NHCOR), or an alkoxide (—OR), where R is a carbyl group.

### Claim 31 (depends on 30)

The method of claim 30, wherein the carbyl groups are the same or different and are selected from the group consisting of an alkyl group, an alkenyl group, an aryl group, an alkaaryl group, an aryalkyl group, or mixtures or combinations thereof.

### Claim 32 (depends on 31)

The method of claim 31, wherein each carbyl group has between about 3 and about 20, where one or more of the carbon atoms can be replaced with a hetero atom selected from the group consisting of oxygen and nitrogen, with the remainder of valences comprising hydrogen or a mono-valent group including a halogen, an amide (—NHCOR), or an alkoxide (—OR), where R is a carbyl group.

### Claim 33 (depends on 31)

The method of claim 31, wherein each carbyl group has between about 3 and about 16, where one or more of the carbon atoms can be replaced with a hetero atom selected from the group consisting of oxygen and nitrogen, with the remainder of valences comprising hydrogen or a mono-valent group including a halogen, an amide (—NHCOR), or an alkoxide (—OR), where R is a carbyl group.

### Claim 34 (depends on 31)

The method of claim 31, wherein each carbyl group has between about 3 and about 12, where one or more of the carbon atoms can be replaced with a hetero atom selected from the group consisting of oxygen and nitrogen, with the remainder of valences comprising hydrogen or a mono-valent group including a halogen, an amide (—NHCOR), or an alkoxide (—OR), where R is a carbyl group.

### Claim 35 (depends on 31)

The method of claim 31, wherein each carbyl group has between about 4 and about 8, where one or more of the carbon atoms can be replaced with a hetero atom selected from the group consisting of oxygen and nitrogen, with the remainder of valences comprising hydrogen or a mono-valent group including a halogen, an amide (—NHCOR), or an alkoxide (—OR), where R is a carbyl group.

### Claim 36 (depends on 29)

The method of claim 29, wherein R1, R2, and R3 are alkyl groups having from about 3 to about 20 carbon atoms, where one or more of the carbon atoms can be replaced with a hetero atom selected from the group consisting of oxygen and nitrogen, with the remainder of valences comprising hydrogen or a mono-valent group including a halogen, an amide (—NHCOR), or an alkoxide (—OR), where R is a carbyl group.

### Claim 37 (depends on 29)

The method of claim 29, wherein R1, R2, and R3 are alkyl groups having from about 4 to about 12 carbon atoms, where one or more of the carbon atoms can be replaced with a hetero atom selected from the group consisting of oxygen and nitrogen, with the remainder of valences comprising hydrogen or a mono-valent group including a halogen, an amide (—NHCOR), or an alkoxide (—OR), where R is a carbyl group.

### Claim 38 (depends on 29)

The method of claim 29, wherein R1, R2, and R3 are alkyl groups having 4 to about 8 carbon atoms, where one or more of the carbon atoms can be replaced with a hetero atom selected from the group consisting of oxygen and nitrogen, with the remainder of valences comprising hydrogen or a mono-valent group including a halogen, an amide (—NHCOR), or an alkoxide (—OR), where R is a carbyl group.