Method of controlling gas hydrates in fluid systems

Patent metadata

Field	Value
Publication number	US-9550935-B2
Application number	US-201414582618-A
Country	US
Kind code	B2
Filing date	Dec 24, 2014
Priority date	Oct 17, 2008
Publication date	Jan 24, 2017
Grant date	Jan 24, 2017

Abstract

A method of inhibiting hydrates in a fluid comprising water and gas comprising adding to the fluid an effective hydrate-inhibiting amount of a composition comprising one or more copolymers of N-alkyl (alkyl)acrylamide monomers and one or more cationic monomers selected from acid and alkyl chloride quaternary salts of N,N-dialkylaminoalkyl (meth)acrylates and N,N-dialkylaminoalkyl (meth)acrylamides.

First claim

What is claimed is:

1. A method of inhibiting hydrate formation in a fluid comprising water, gas and optionally liquid hydrocarbon comprising treating the fluid with an effective hydrate-inhibiting amount of an inhibitor composition comprising a cationic copolymer derived by polymerization of about 75 to about 99.9 mole percent of N-alkyl alkylacrylamide or N-alkyl acrylamide monomer units and about 0.1 to about 25 mole percent of alkylacrylamidoalkyltrialkylammonium chloride or acrylamidoalkyltrialkylammonium chloride monomer units.

2. The method of claim 1 , wherein polymerization of said cationic copolymer is initiated by redox decomposition of a peroxide with a redox co-catalyst.

3. The method of claim 2 , wherein the redox co-catalyst is CuSO 4 or Fe 2 (SO 4 ) 3 .

4. The method of claim 1 , wherein said cationic copolymer has a molecular weight distribution of about 60-100 percent in the range of 1,000 to 20,000 Daltons and 0-25 percent in the range from 20,000 to 6,000,000 Daltons.

5. The method of claim 1 , wherein said inhibitor composition further comprises a hydroxyl-containing compound selected from the group consisting of a low molecular weight alcohol, a low molecular weight glycol, a low molecular weight glycol ether, and combinations thereof.

6. The method of claim 5 , wherein said hydroxyl-containing compound is selected from the group consisting of isopropanol; 1,1,1-tris(hydroxymethyl) propane; triethylene glycol dimethyl ether; diethylene glycol dimethyl ether; 2-ethoxyethanol; diethylene glycol monomethyl ether; ethylene glycol monobutyl ether; diethylene glycol monoethyl ether; diethylene glycol monobutyl ether; and combinations thereof.

7. The method of claim 1 , wherein said cationic copolymer has an average molecular weight of about 1,000 to about 100,000 Dalton.

8. The method of claim 1 , further comprising treating the fluid with a corrosion-inhibiting amount of a corrosion inhibitor.

9. The method of claim 8 , wherein the corrosion inhibitor is water soluble.

10. The method of claim 9 , wherein the corrosion inhibitor is selected from the group consisting of a quaternary amine-based corrosion inhibitor, an imidazoline-based corrosion inhibitor, a phosphate ester-based corrosion inhibitor, and combinations thereof.

11. The method of claim 9 , wherein the water soluble corrosion inhibitor is a quaternary amine-based corrosion inhibitor.

12. The method of claim 1 , wherein the inhibitor composition further comprises a corrosion inhibitor.

13. The method of claim 12 , wherein the corrosion inhibitor is water soluble.

14. The method of claim 13 , wherein the corrosion inhibitor is selected from the group consisting of a quaternary amine-based corrosion inhibitor, an imidazoline-based corrosion inhibitor, a phosphate ester-based corrosion inhibitor, and combinations thereof.

15. The method of claim 13 , wherein the water soluble corrosion inhibitor is a quaternary amine-based corrosion inhibitor.

16. The method of claim 1 , wherein the N-alkyl acrylamide monomer is N-isopropyl acrylamide.

17. The method of claim 1 , wherein the N-alkyl (alkyl)acrylamide monomer is N-isopropyl methacrylamide.

18. The method of claim 1 , wherein the acrylamidoalkyltrialkylammonium chloride monomer is acrylamidopropyltrimethylammonium chloride.

19. The method of claim 1 , wherein the alkylacrylamidoalkyl-trialkylammonium chloride monomer is methacrylamidopropyltrimethylammonium chloride.

20. The method of claim 1 , wherein the N-alkyl (alkyl)acrylamide monomer is N-isopropyl methacrylamide and the alkylacrylamidoalkyltrialkylammonium chloride monomer is methacrylamidopropyltrimethylammonium chloride.

21. The method of claim 1 , wherein the cationic copolymer derived by polymerization of monomers consisting essentially of about 75 to about 99.9 mole percent of N-alkyl alkylacrylamide or N-alkyl acrylamide monomer units and about 0.1 to about 25 mole percent of alkylacrylamidoalkyltrialkylammonium chloride or acrylamidoalkyltrialkylammonium chloride monomer units.

22. The method of claim 1 , wherein the cationic copolymer derived by polymerization of monomers consisting of about 75 to about 99.9 mole percent of N-alkyl alkylacrylamide or N-alkyl acrylamide monomer units and about 0.1 to about 25 mole percent of alkylacrylamidoalkyltrialkylammonium chloride or acrylamidoalkyltrialkylammonium chloride monomer units.

Assignees

• Nalco Co

Inventors

• Conrad Peter G
• Acosta Erick J
• Mcnamee Kevin P
• Bennett Brian
• Lindeman Olga E S
• Carlise Joseph R

Classifications

• C10L3/108

  Production of gas hydrates · CPC title

• C09K2208/22

  Hydrates inhibition by using well treatment fluids containing inhibitors of hydrate formers · CPC title

• C10L3/10

  Working-up natural gas or synthetic natural gas · CPC title

• C10L3/003

  Additives for gaseous fuels · CPC title

• C09K8/524 Primary

  organic depositions, e.g. paraffins or asphaltenes · CPC title