Method of inhibiting the formation of gas hydrates using amidines and guanidines
The present invention relates to methods of inhibiting the formation or agglomeration of gas hydrates using amidines or guanidines. The invention further relates to compositions comprising amidines or guanidines that find use as gas hydrate inhibitors, as well as processes for preparing alkylated amidinium or guanidinium salts.
1. A method of inhibiting the formation or agglomeration of gas hydrates in a system, said method comprising adding to the system a compound containing one or more units of formula (Ia)
said compound optionally further comprising one or more units of formula (I)
wherein:
R 1 , R 2 , R 3 and R 4 are independently an organic group comprising 1-20 carbon atoms and optionally one or more heteroatoms, R 5 is either an organic group comprising 1-20 carbon atoms and optionally one or more heteroatoms or R 5 is NR 6 R 7 where R 6 and R 7 are an organic group comprising 1-20 carbon atoms and optionally one or more heteroatoms,
wherein R 1 -R 7 may optionally act as a linker either to an adjacent unit of formula (I) or (Ia) or to a polymer chain, and
wherein at least two of R 1 -R 7 denote C 2-6 alkyl.
2. The method as claimed in claim 1 , wherein R 5 is NR 6 R 7 .
3. The method as claimed in claim 1 , wherein
R 1 -R 4 , R 6 and R 7 denote C 2 -C 6 alkyl;
R 5 denotes NR 6 R 7 or C 2-6 alkyl; such that
at least two of R 1 -R 7 denote C 3-5 alkyl,
wherein R 1 -R 7 may optionally act as a linker either to an adjacent unit of formula (I) or (Ia) or to a polymer chain.
4. The method as claimed in claim 1 , wherein when acting as
a linker to an adjacent unit of formula (I) or (Ia), R 1 -R 7 denotes C 2-6 alkylene.
5. The method as claimed in claim 1 , wherein
R 1 -R 4 , R 6 and R 7 denote C 3-5 alkyl;
R 5 denotes NR 6 R 7 or C 3-5 alkyl;
wherein R 1 -R 7 may optionally denote C 3-5 alkylene which acts as a linker either to an adjacent unit of formula (I) or (Ia) or to a polymer chain.
6. The method as claimed in claim 1 in which one or more of R 1 -R 7 are independently chosen from n-butyl, n-pentyl and iso-pentyl groups.
7. The method as claimed in claim 1 , wherein the compound is an oligomer or a polymer.
8. The method as claimed in claim 7 , wherein the unit of formula (I) or (Ia) is a pendant group of a poly(meth)acrylate, poly(meth)acrylamide or a polymer or copolymer of N-vinylcaprolactam.
9. The method as claimed in claim 1 , wherein said system is configured for hydrocarbon drilling, production, storage and/or transportation, including production, drilling, completion, fracturing, stimulation and injection and re-injection operations.
10. The method as claimed in claim 1 , wherein said method inhibits the formation of gas hydrates and said compound is a polymer.
11. The method as claimed in claim 1 , wherein said method inhibits the formation of gas hydrates and said compound comprises one or more units of Formula (II) or (IIa):
12. The method as claimed in claim 1 , wherein said method inhibits the agglomeration of gas hydrates and said compound comprises one or more units of Formula (Ia) or (IIa):
13. The method as claimed in claim 1 , further comprising adding a kinetic hydrate inhibitor to said system.
14. A method of inhibiting the formation or agglomeration of gas hydrates in a system, said method comprising adding to the system a polymer containing one or more units of formula (I) or formula (Ia)
wherein
R 1 , R 2 , R 3 and R 4 are independently an organic group comprising 1-20 carbon atoms and optionally one or more heteroatoms, R 5 is either an organic group comprising 1-20 carbon atoms and optionally one or more heteroatoms or R 5 is NR 6 R 7 where R 6 and R 7 are an organic group comprising 1-20 carbon atoms and optionally one or more heteroatoms,
wherein R 1 -R 7 may optionally act as a linker either to an adjacent unit of formula (I) or (Ia) or to a polymer chain, and
wherein at least two of R 1 -R 7 denote C 2-6 alkyl,
wherein the unit of formula (I) or (Ia) is a pendant group of a poly(meth)acrylate, poly(meth)acrylamide or a polymer or copolymer of N-vinylcaprolactam.
15. The method as claimed in claim 14 , wherein said compound comprises one or more units of formula (Ia).
16. The method as claimed in claim 14 , wherein R 5 is NR 6 R 7 .
17. The method as claimed in claim 14 , wherein R 1 -R 4 , R 6 and R 7 denote C 2 -C 6 akyl;
R 5 denotes NR 6 R 7 or C 2 -C 6 alkyl; such that at least two of R 1 -R 7 denote C 3-5 alkyl, wherein R 1 -R 7 may optionally act as a linker either to an adjacent unit of formula (I) or (Ia) or to a polymer chain.
18. The method as claimed in claim 14 , wherein when acting as a linker to an adjacent unit of formula (I) or (Ia), R 1 -R 7 denotes C 2-6 alkylene.
19. The method as claimed in claim 14 , wherein R 1 -R 4 , R 6 and R 7 denote C 3-5 akyl;
R 5 denotes NR 6 R 7 or C 3-5 alkyl;
wherein R 1 -R 7 may optionally denote C 3-5 alkylene which acts as a linker either to an adjacent unit of formula (I) or (Ia) or to a polymer chain.
20. The method as claimed in claim 14 in which one or more of R 1 -R 7 are independently chosen from n-butyl, n-pentyl and iso-pentyl groups.
21. The method as claimed in claim 14 , wherein said system is configured for hydrocarbon drilling, production, storage and/or transportation, including production, drilling, completion, fracturing, stimulation and injection and re-injection operations.
22. The method as claimed in claim 14 , wherein said method inhibits the formation of gas hydrates and said compound is a polymer.
23. The method as claimed in claim 14 , wherein said method inhibits the formation of gas hydrates and said compound comprises one or more units of Formula (II) or (IIa):
24. The method as claimed in claim 14 , wherein said method inhibits the agglomeration of gas hydrates and said compound comprises one or more units of Formula (Ia) or (IIa):
25. The method as claimed in claim 14 , further comprising adding a kinetic hydrate inhibitor to said system.
26. A method of inhibiting the agglomeration of gas hydrates in a system, said method comprising adding to the system a compound containing one or more units of of Formula (Ia) or (IIa):
said compound optionally further comprising one or more units of formula (I)
wherein
R 1 , R 2 , R 3 and R 4 are independently an organic group comprising 1-20 carbon atoms and optionally one or more heteroatoms, R 5 is either an organic group comprising 1-20 carbon atoms and optionally one or more heteroatoms or R 5 is NR 6 R 7 where R 6 and R 7 are an organic group comprising 1-20 carbon atoms and optionally one or more heteroatoms,
wherein R 1 -R 7 may optionally act as a linker either to an adjacent unit of formula (I) or (Ia) or to a polymer chain, and
wherein at least two of R 1 -R 7 denote C 2-6 alkyl.
27. The method as claimed in claim 26 , wherein said compound comprises one or more units of formula (Ia).
28. The method as claimed in claim 26 , wherein R 5 is NR 6 R 7 .
29. The method as claimed in claim 26 , wherein
R 1 -R 4 , R 6 and R 7 denote C 2 -C 6 akyl;
R 5 denotes NR 6 R 7 or C 2-6 alkyl; such that
at least two of R 1 -R 7 denote C 3-5 alkyl,
wherein R 1 -R 7 may optionally act as a linker either to an adjacent unit of formula (I) or (Ia) or to a polymer chain.
30. The method as claimed in claim 26 , wherein when acting as a linker to an adjacent unit of formula (I) or (Ia), R 1 -R 7 denotes C 2-6 alkylene.
31. The method as claimed in claim 1 , wherein
R 1 -R 4 , R 6 and R 7 denote C 3-5 akyl;
R 5 denotes NR 6 R 7 or C 3-5 alkyl;
wherein R 1 -R 7 may optionally denote C 3-5 alkylene which acts as a linker either to an adjacent unit of formula (I) or (Ia) or to a polymer chain.
32. The method as claimed in claim 26 in which one or more of R 1 -R 7 are independently chosen from n-butyl, n-pentyl and iso-pentyl groups.
33. The method as claimed in claim 26 , wherein the compound is an oligomer or a polymer.
34. The method as claimed in claim 33 , wherein the unit of formula (I) or (Ia) is a pendant group of a poly(meth)acrylate, poly(meth)acrylamide or a polymer or copolymer of N-vinylcaprolactam.
35. The method as claimed in claim 26 , wherein said system is configured for hydrocarbon drilling, production, storage and/or transportation, including production, drilling, completion, fracturing, stimulation and injection and re-injection operations.
36. The method as claimed in claim 26 , wherein said method inhibits the agglomeration of gas hydrates and said compound comprises one or more units of Formula (Ia) or (IIa):
37. The method as claimed in claim 26 , further comprising adding a kinetic hydrate inhibitor to said system.