# US 10,370,581 B2 · Gas hydrate inhibitor, method and use of hyperbranched polyester polyols as gas hydrate inhibitors

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- Number: US 10,370,581 B2
- Document ID: US10370581B2
- Status: Granted
- Kind: B2
- Application number: 14/438,276
- Filed: 2013-10-28
- Published: 2015-09-10
- Granted: 2019-08-06
- Earliest claimed: 2012-10-26
- Assignees: Sinvent AS
- Applicants: Sinvent AS
- Inventors: Martin Fossen; Helene Konstantia Vralstad
- Web page: https://patentgrep.com/patent/US10370581B2

## CPC

- C09K 8/52: Compositions for preventing, limiting or eliminating depositions, e.g. for cleaning
- C07C 69/67: of saturated acids
- C08G 63/91: Polymers modified by chemical after-treatment
- C10L 3/107: {Limiting or prohibiting hydrate formation}
- C09K 2208/22: Hydrates inhibition by using well treatment fluids containing inhibitors of hydrate formers
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C10L: FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS

## Abstract

The present invention relates to a non-toxic and biodegradable low dosage gas hydrate inhibitor comprising hyper-branched polyester polyols having hydroxyl end groups which are chemically modified. Further, the invention relates to a method for controlling gas hydrate formation and plugging of gas hydrate forming fluids and the use of the gas hydrate inhibitors for this purpose.

## Claims

### Claim 1

A method for controlling gas hydrate formation and plugging in gas hydrate forming fluids, said method comprising:
adding a gas hydrate inhibitor comprising hyperbranched polyester polyols to crude oil, condensate, and gas systems containing water;
wherein the hyperbranched polyester polyols do not contain polyesteramide polyols, and
wherein the hyperbranched polyester polyols have hydroxyl end groups which are chemically modified with a hydrophilic group and/or a hydrophobic group.

### Claim 2 (depends on 1)

The method for controlling gas hydrate formation according to claim 1, wherein the hyperbranched polyester polyols are non-toxic and biodegradable.

### Claim 3 (depends on 1)

The method for controlling gas hydrate formation according to claim 1, wherein all or parts of the chemically modified hydroxyl end groups are esterified with at least one hydrophilic group for increased water solubility.

### Claim 4 (depends on 1)

The method for controlling gas hydrate formation according to claim 1, wherein all or parts of the chemically modified hydroxyl end groups are esterified with at least one hydrophobic group for increased amphiphilicity and hydrate interaction and/or increased oil solubility.

### Claim 5 (depends on 4)

The method for controlling gas hydrate formation according to claim 4, wherein the hydrophobic group is introduced by reaction of the hyperbranched polyester polyol with a carboxylicacid and/or a carboxylic anhydride.

### Claim 6 (depends on 5)

The method for controlling gas hydrate formation according to claim 5, wherein the carboxylic acid is selected from the group consisting of pivalic acid, dimethylbutyric acid, trimethylpentanoic acid, tert-butyl-trimethylpentanoic acid, diethylhexanoic acid, and cyclopentanoic acid.

### Claim 7 (depends on 5)

The method for controlling gas hydrate formation according to claim 5, wherein the carboxylic anhydride is pivalic anhydride.

### Claim 8 (depends on 1)

The method for controlling gas hydrate formation according to claim 1, wherein the chemically modified hydroxyl groups are replaced with amphiphilic groups.

### Claim 9 (depends on 1)

The method according to claim 1, wherein the gas hydrate inhibitor is added alone or in combination with synergists.

### Claim 10 (depends on 9)

The method according to claim 9, wherein the synergist is selected from the group consisting of n-butanol, chitosan, 2-butoxyethanol, propanol, polysuccinimide, methanol, glycols, and non-polymeric surfactants with caprolactam or alkylamide head groups.

### Claim 11 (depends on 9)

The method according to claim 9, wherein the gas hydrate inhibitor is dissolved in a solvent before being added to the crude oil, condensate, and gas systems containing water.

### Claim 12 (depends on 11)

The method according to claim 11, wherein the solvent is selected from the group consisting of water, alcohols, aliphatic solvent, aromatic solvents, mineral oils, esters, and ethers.