Methods of dissolving gas hydrates

Patent metadata

Field	Value
Publication number	US-11518924-B2
Application number	US-202017090138-A
Country	US
Kind code	B2
Filing date	Nov 5, 2020
Priority date	Nov 5, 2020
Publication date	Dec 6, 2022
Grant date	Dec 6, 2022

Abstract

A method of dissolving a gas hydrate in a pipeline includes introducing a gas hydrate dissolving solution into the pipeline and allowing the gas hydrate dissolving solution to at least partially dissolve the gas hydrate in the pipeline. The gas hydrate dissolving solution includes cesium formate, potassium formate, or both, and has a flash point of greater than 50° C.

First claim

What is claimed is:

1. A method of dissolving a gas hydrate in a pipeline comprising:
introducing a gas hydrate dissolving solution into the pipeline in multiple injections, in which:
subsequent injections of the gas hydrate dissolving solution after a first injection of the gas hydrate dissolving solution are a lesser volume of gas hydrate dissolving solution based on a total volume of water in the pipeline than the first injection,
the gas hydrate dissolving solution comprises cesium formate, potassium formate, or both, and
the gas hydrate dissolving solution has a flash point of greater than 50° C.; and

allowing the gas hydrate dissolving solution to at least partially dissolve the gas hydrate in the pipeline.

2. The method of claim 1 , in which introducing the gas hydrate dissolving solution comprises introducing from 2 to 7 injections of the gas hydrate dissolving solution, in which:
the first injection is from 5 to 15 vol. % gas hydrate dissolving solution, based on a total volume of water in the pipeline;
each remaining injection is from 3 to 7 vol. % of gas hydrate dissolving solution, based on a total volume of water in the pipeline; and
each remaining injection is a lesser vol. % gas hydrate dissolving solution than the first injection.

3. The method of claim 1 , in which introducing the gas hydrate dissolving solution comprises introducing from 1 to 40 vol. % gas hydrate dissolving solution, based on a total volume of water in the pipeline.

4. The method of claim 1 , in which allowing the gas hydrate dissolving solution to at least partially dissolve the gas hydrate takes less than 4 hours.

5. The method of claim 1 , in which allowing the gas hydrate dissolving solution to dissolve the gas hydrate takes less than 2 hours.

6. The method of claim 1 , further comprising heating the gas hydrate dissolving solution prior to introducing the gas hydrate dissolving solution into the pipeline.

7. The method of claim 6 , further comprising heating the gas hydrate dissolving solution to at least 100° F.

8. The method of claim 6 , further comprising heating the gas hydrate dissolving solution to from 100° F. to 300° F.

9. The method of claim 6 , in which introducing the gas hydrate dissolving solution comprises introducing from 2 to 5 injections of the gas hydrate dissolving solution, in which
the first injection is from 1 to 4 vol. % gas hydrate dissolving solution, based on a total volume of water in the pipeline;
each remaining injection is from 1 to 3 vol. % gas hydrate dissolving solution, based on a total volume of water in the pipeline; and
each remaining injection is a lesser vol. % gas hydrate dissolving solution than the first injection.

10. The method of claim 6 , in which introducing the gas hydrate dissolving solution comprises introducing from 5 to 10 vol. % gas hydrate dissolving solution, based on a total volume of water in the pipeline.

11. The method of claim 1 , in which the gas hydrate dissolving solution has a flash point of greater than 60° C.

12. The method of claim 1 , in which the gas hydrate dissolving solution has a melting point of less than −15° C.

13. The method of claim 1 , in which the gas hydrate dissolving solution comprises an aqueous solution comprising the cesium formate, potassium formate, or both.

14. The method of claim 1 , further comprising inhibiting gas hydrate formation in the pipeline after introducing the gas hydrate dissolving solution.

15. The method of claim 1 , in which a pressure of the pipeline is greater than 500 psi and a temperature of the pipeline is less than 100° F.

16. The method of claim 1 , in which the gas hydrate comprises free water, carbon dioxide, hydrogen sulfide, methane, ethane, propane, n-butane, iso-butane, or combinations thereof.

17. The method of claim 1 , further comprising allowing hydrocarbon fluid to flow through the pipeline during introducing the gas hydrate dissolving solution, where the hydrocarbon fluid comprises methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, carbon dioxide, hydrogen sulfide, dinitrogen, or combinations of these.

18. The method of claim 1 , further comprising allowing the dissolved gas hydrate to discharge from the pipeline after allowing the gas hydrate dissolving solution to at least partially dissolve the gas hydrate in the pipeline.

19. The method of claim 1 , in which introducing the gas hydrate dissolving solution into the pipeline comprises introducing the gas hydrate dissolving solution at an injection rate of from 0.5 gal/min to 20 gal/min.

20. The method of claim 1 , in which the gas hydrate dissolving solution further comprises a corrosion inhibitor, a scale inhibitor, a demulsifier, or combinations thereof.

Assignees

• Saudi Arabian Oil Co

Inventors

• Saini Rajesh Kumar
• Sayed Mohammed

Classifications

• C10L2290/141

  of additive or catalyst · CPC title

• C09K2208/22

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

• C10L3/107 Primary

  Limiting or prohibiting hydrate formation · CPC title

• C09K8/52 Primary

  Compositions for preventing, limiting or eliminating depositions, e.g. for cleaning · CPC title

• C10L2270/10

  for transport, e.g. in pipelines as a gas hydrate slurry · CPC title