Synergistic Blends Of Anti-Agglomerant Gas Hydrate Inhibitors With Quaternary Alkyl Ammonium Compounds

Abstract

The present disclosure relates to a gas hydrate inhibitor composition comprising from an amphiphile having a hydrophobic tail linked to a hydrophilic head group by a linking moiety, the amphiphile having the general formula (1)

[R.sup.5-L-N(R.sup.1)(R.sup.2)(R.sup.3)].sup.+X.sup.−  (1) wherein each of R.sup.1and R.sup.2 is independently an alkyl group having from 1 to 5 carbon atoms; or wherein the nitrogen atom and the R.sup.1and R.sup.2 groups together form a substituted or unsubstituted heterocyclic group; R.sup.3 is present or not as hydrogen or an alkyl group having from 1 to 8 carbon atoms which optionally bears a hydroxy group or a carboxy group in the 2-position; L is a linking moiety comprising an optionally substituted hydrocarbyl group having at least 2 adjacent carbon atoms, at least one heteroatom selected from nitrogen and oxygen, and optionally one or more further heteroatoms; R.sup.5 is a hydrocarbyl group having from 6 to 22 carbon atoms; and X.sup.− is present as an anion when R.sup.3 is present; and

from a cationic surfactant which is selected from di(C.sub.8-C.sub.18 alkyl)dimethyl ammonium salts.

Claims

1. A gas hydrate inhibitor composition comprising A) from 5 to 95 weight-% of an amphiphile having a hydrophobic tail linked to a hydrophilic head group by a linking moiety, the amphiphile having the general formula (1)
[R.sup.5-L-N(R.sup.1)(R.sup.2)(R.sup.3)].sup.+X.sup.−  (1) wherein each of R.sup.1and R.sup.2 is independently an alkyl group having from 1 to 5 carbon atoms; or wherein the nitrogen atom and the R.sup.1and R.sup.2 groups together form a substituted or unsubstituted heterocyclic group; R.sup.3 is present or not as hydrogen or an alkyl group having from 1 to 8 carbon atoms which optionally bears a hydroxy group or a carboxy group in the 2-position; L is a linking moiety comprising an optionally substituted hydrocarbyl group having at least 2 adjacent carbon atoms, at least one heteroatom selected from nitrogen and oxygen, and optionally one or more further heteroatoms; R.sup.5 is a hydrocarbyl group having from 6 to 22 carbon atoms; and X.sup.− is present as an anion when R.sup.3 is present; and B) from 5 to 95 weight-% of a cationic surfactant which is selected from di(C.sub.8-C.sub.18 alkyl)dimethyl ammonium salts.

2. The gas hydrate inhibitor composition according to claim 1, wherein R.sup.1and R.sup.2 independently are alkyl groups having from 3 to 5 carbon atoms.

3. The gas hydrate inhibitor composition according to claim 1 wherein R.sup.5 is an alkyl or alkenyl group having between 8 and 20 carbon atoms.

4. The gas hydrate inhibitor composition according to claim 1, wherein R.sup.3 is present as hydrogen or as a methyl group.

5. The gas hydrate inhibitor according to claim 1, wherein X.sup.− is selected from the group consisting of hydroxide, carboxylate, halide, sulphate, nitrite, nitrate, organic sulfonate, phosphate, organic phosphonate and combinations thereof.

6. The gas hydrate inhibitor composition according to claim 1, wherein X.sup.− is a carboxylate anion.

7. The gas hydrate inhibitor composition according to claim 6, wherein the carboxylate anion is selected from the group consisting of formate, acetate, propionate, acrylate, methacrylate and any combination thereof.

8. The gas hydrate inhibitor composition according to claim 1, wherein the linking moiety L contains a connecting chain which constitutes the direct connection between the hydrophilic head group —N(R.sup.1)(R.sup.2) respectively —[N(R.sup.1)(R.sup.2)(R.sup.3)].sup.+X.sup.− and the lipophilic tail R.sup.5, which comprises at least 2 adjacent carbon atoms, at least one heteroatom selected from nitrogen and oxygen and optionally one or more further heteroatoms and which may have substituents attached to it.

9. The gas hydrate inhibitor composition according to claim 8, wherein the connecting chain is an optionally substituted heteroaliphatic chain comprising at least one heteroatom selected from nitrogen and oxygen.

10. The gas hydrate inhibitor composition according to claim 9, wherein the at least one heteroatom is nitrogen.

11. The gas hydrate inhibitor composition according to claim 8, wherein the connecting chain is a heteroaliphatic chain wherein one or more non-adjacent CH.sub.2 groups are replaced by a heteroatom selected from nitrogen and oxygen and optionally by one or more further heteroatom(s) which are part of a functional group selected from the group consisting of —C(═O)—O—, —O—C(═O)—, —C(═O)—NR.sup.6—, —NR.sup.7—C(═O), —NR.sup.6—, —R.sup.7N—, —O—, —S—, —(SO)—or —(SO.sub.2)—, wherein R.sup.6 is hydrogen or an alkyl group having from 1 to 5 carbon atoms, and R.sup.7 is hydrogen or an organic moiety having from 1 to 20 carbon atoms.

12. The gas hydrate inhibitor composition according to claim 8, wherein the connecting chain comprises one or more aliphatic groups having 2 to 10 adjacent carbon atoms, which are connected to each other and/or the hydrophobic tail by a heteroatom which may be part of a functional group selected from the group consisting of —C(═O)—O—, —O—C(═O)—, —C(═O)—N(R.sup.6)—, —N(R.sup.7)—C(═O)—, —N(R.sup.6)—, —(R.sup.7)N—, 13 O—, —S—, —(SO)— or —(SO.sub.2)— wherein R.sup.6 is hydrogen or an alkyl group having from 1 to 5 carbon atoms, and R.sup.7 is hydrogen or an organic moiety having from 1 to 20 carbon atoms.

13. The gas hydrate inhibitor composition according to claim 1, wherein the structure of the linking moiety L corresponds to one out of formulae (2) to (12b)
—C(═O)—N(R.sup.6)—(CH.sub.2).sub.t—  (2)
—N(R.sup.7)—C(═O)—(CH.sub.2).sub.t—  (3)
—N(R.sup.7)—(CH.sub.2).sub.2—C(═O)—NH—(CH.sub.2).sub.t—  (4)
—N(R.sup.7)—C(═O)—(CH.sub.2).sub.2—N(R.sup.6)—(CH.sub.2).sub.t—  (5)
—CH(OH)—CH.sub.2—N(R.sup.6)—(CH.sub.2).sub.t—  (6)
—CH(COOH)—CH.sub.2—C(═O)—N(R.sup.6)—(CH.sub.2).sub.t—  (7a)
—CH(CH.sub.2—COOH)—C(═O)—N(R.sup.6)—(CH.sub.2).sub.t—  (7b) ##STR00011##
−CH(COOH)—CH.sub.2—C(═O)—[O—(CH.sub.2).sub.t].sub.v—  (8a)
—CH(CH.sub.2—COOH)—C(═O)—[O—(CH.sub.2).sub.t].sub.v—  (8b)
—N(R.sup.7)—C(═O)—(CH.sub.2).sub.2—C(═O)—N(R.sup.6)—(CH.sub.2).sub.t—  (9)
—N(R.sup.7)—C(═O)—CH.sub.2—CH(OH)—C(═O)—N(R.sup.6)—(CH.sub.2).sub.t—  (10a)
—N(R.sup.7)—C(═O)—CH(OH)—CH.sub.2—C(═O)—N(R.sup.6)—(CH.sub.2).sub.t—  (10b)
—N(R.sup.7)—C(═O)—CH(OH)—CH(OH)—C(═O)—N(R.sup.6)—(CH.sub.2).sub.t—  (11)
—N(R.sup.7)—C(═O)—C(OH)(CH.sub.2COOH)—CH.sub.2—C(═O)—N(R.sup.6)—(CH.sub.2).sub.t—  (12a)
—N(R.sup.7)—C(═O)—CH.sub.2—C(OH)(CH(COOH)—C(═O)—N(R.sup.6)—(CH.sub.2).sub.t—  (12b) wherein R.sup.6 is hydrogen or an alkyl group having from 1 to 5 carbon atoms, and R.sup.7 is hydrogen or an organic moiety having from 1 to 20 carbon atoms.

14. The gas hydrate inhibitor composition according to claim 1 wherein the amphiphile (A) is an amido amine according to the general formula (13) ##STR00012## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.5 and X.sup.− have the general meanings given above for formula (1) and its preferred embodiments; R.sup.4 is selected from the group consisting of —(CH.sub.2).sub.t—, —[(CH.sub.2—CHR.sup.10).sub.s]—, —(CH.sub.2−CHR.sup.10O).sub.u—(CH.sub.2).sub.t— and combinations thereof; R.sup.6 is hydrogen or an alkyl group having from 1 to 5 carbon atoms; R.sup.7 is hydrogen or an organic moiety having from 1 to 20 carbon atoms; R.sup.8 is present or not as hydrogen or an alkyl group having from 1 to 5 carbon atoms; with the proviso that when m=0, R.sup.8 is not present; R.sup.9 is present or not as hydrogen or an alkyl group having from 1 to 5 carbon atoms; with the proviso that when o=0, R.sup.9 is not present; R.sub.10 is an alkyl group having 1 to 4 carbon atoms; m is 0 or 2, n is 0 or 1, o is 0 or 2, p is 0 or an integer between 1and 5; q is 0 or an integer between 1and 6, but is not more than the sum of n+p n+p is an integer between 1and 6, and prcfcrably is 1; s is 1, 2 or 3; t is 2, 3 or 4; and u is an integer between 1and 100.

15. The gas hydrate inhibitor composition according to claim 1 wherein the amphiphile (A) is an amido amine according to the general formula (14) ##STR00013## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.5 and X.sup.− have the general meanings given above; R.sup.4 is selected from —(CH.sub.2).sub.t— and —[(CH.sub.2—CHR.sup.10).sub.s]—; R.sup.6 is hydrogen or an alkyl group having from 1 to 5 carbon atoms; R.sup.10 is an alkyl group having 1 to 4 carbon atoms; p is an integer between 1and 5; s is 1, 2 or 3; t is 2, 3 or 4; q is 0 when R.sup.3 is absent, or q is 1 when R.sup.3 is present.

16. The gas hydrate inhibitor composition according to claim 15, wherein the compound according to formula (14) is the reaction product of an N,N-dialkyl-aminoalkylamine of formula HN(R.sup.6)—R.sup.4—N(R.sup.1)(R.sup.2) with a fatty acid, a fatty acid ester or a glyceride.

17. The gas hydrate inhibitor composition according to claim 15, wherein the compound according to formula (14) includes a product prepared by the reaction of an amine selected from (3-dialkylamino)propylamine and (3-dialkylamino)ethylamine with a vegetable oil or tallow oil, followed by either neutralization with an acid selected from mineral acids and carboxylic acids having from 1 to 20 carbon atoms, or followed by quaternization with an alkylating agent selected from an organic halide, dimethyl sulfate, diethyl sulfate and C.sub.2-C.sub.4 alkylene oxides, and wherein the dialkyl amino group of the (3-dialkylamino)propylamine includes two alkyl groups independently selected from the group consisting of methyl, ethyl, propyl, butyl, and combinations thereof or, wherein R.sup.1and R.sup.2 together with the nitrogen atom to which they are attached form a substituted or unsubstituted heterocyclic group having 5 or 6 atoms in the ring.

18. The gas hydrate inhibitor composition according to claim 1, wherein the amphiphile (A) is an amido amine according to one or more of formulae (15), (16) and/or (17): ##STR00014## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.5 and X.sup.− have the meanings given above for formula (1); R.sup.4 is —(CH.sub.2).sub.t−; R.sup.6 is hydrogen or an alkyl group having from 1 to 5 carbon atoms; R.sup.7 is hydrogen or an organic moiety having 1 to 20 carbon atoms; R.sup.8 and R.sup.9 independently is present or not as hydrogen or an alkyl group having from 1 to 5 carbon atoms; q is 0 when R.sup.3, R.sup.8 and R.sup.9 are absent; and q is 1, 2 or 3 depending on the presence of one or more of R.sup.3, R.sup.8 and/or R.sup.9; and t is 2, 3 or 4.

19. The gas hydrate inhibitor composition according to claim 1 wherein the cationic surfactant (B) is a quaternary ammonium compound of the formula (19): ##STR00015## wherein R.sup.11and R.sup.12 independently from each other are alkyl groups having 8 to 18 carbon atoms and Y.sup.− is an anion.

20. The gas hydrate inhibitor composition according to claim 19, wherein Y.sup.− is selected from the group consisting of bromide, chloride, hydroxide, methosulfate, ethosulfate and combinations thereof.

21. The gas hydrate inhibitor composition according to claim 1, wherein the portion of the cationic surfactant (B) is between 10 and 85 wt.-% based on the combined weights of (A) and (B).

22. The gas hydrate inhibitor composition according to claim 1, wherein the weight ratio between amphiphile (A) and cationic surfactant (B) is between 20:1and 1:20.

23. The gas hydrate inhibitor composition according to claim 1, additionally containing up to 30 wt.-% of a further surfactant (C) being different from (A) and (B), based on the combined masses of (A) and (B).

24. The gas hydrate inhibitor composition according to claim 1, containing 1 to 30 wt.-% of at least one further surfactant (C) being different from (A) and (B), selected from the group consisting of anionic, nonionic, amphoteric and/or cationic surfactants.

25. The gas hydrate inhibitor composition according to claim 1, wherein the composition further comprises at least one kinetic gas hydrate inhibitor being different from (A), (B) and (C).

26. A gas hydrate inhibitor formulation comprising the gas hydrate inhibitor composition according to claim 1, and at least one diluent.

27. The gas hydrate inhibitor formulation according to claim 26, wherein the diluent is selected from monohydric lower alcohols, glycols, ether solvents, ketonic solvents, esters, acetonitrile, water, and aliphatic, aromatic, alkylaromatic solvents, and mixtures thereof.

28. The gas hydrate inhibitor formulation according to claim 26, wherein the diluent is present in the inhibitor formulation in the range from 0.1wt.-% to 95 wt.-%, based on the combined weight of (A), (B), optionally (C) and the diluent.

29. A method for inhibiting the formation of gas hydrate agglomerates and/or plugs, the method comprising bringing a system containing hydrocarbons and water susceptible to gas hydrate formation into contact with a composition comprising A) from 5 to 95 weight-% of an amphiphile having a hydrophobic tail linked to a hydrophilic head group by a linking moiety, the amphiphile having the general formula (1)
[R.sup.5-L-N(R.sup.1)(R.sup.2)(R.sup.3)].sup.+X.sup.−  (1) wherein each of R.sup.1and R.sup.2 is independently an alkyl group having from 1 to 5 carbon atoms; or wherein the nitrogen atom and the R.sup.1and R.sup.2 groups together form a substituted or unsubstituted heterocyclic group; R.sup.3 is present or not as hydrogen or an alkyl group having from 1 to 8 carbon atoms which optionally bears a hydroxy group or a carboxy group in the 2-position; L is a linking moiety comprising an optionally substituted hydrocarbyl group having at least 2 adjacent carbon atoms, at least one heteroatom selected from nitrogen and oxygen, and optionally one or more further heteroatoms; R.sup.5 is a hydrocarbyl group having from 6 to 22 carbon atoms; and X.sup.− is present as an anion when R.sup.3 is present; and B) from 5 to 95 weight-% of a cationic surfactant which is selected from di(C.sub.8-C.sub.18 alkyl)dimethyl ammonium salts.

30. The method according to claim 29, wherein the pressure during contacting is at or greater than atmospheric pressure.

31. The method according to claim 29, wherein the hydrocarbon is a naturally produced gas with the major part of the gas being C.sub.1-C.sub.5 hydrocarbons.

32. (canceled)

33. A method for improving the hydrate inhibitor performance of an amphiphile (A) having the general formula (1)
[R.sup.5-L-N(R.sup.1)(R.sup.2)(R.sup.3)].sup.+X.sup.−  (1) comprising the step of adding a cationic surfactant (B) selected from the group consisting of di(C.sub.8-C.sub.18 alkyl)dimethyl ammonium salts to the amphiphile (A), wherein the cationic surfactant is added to (A) in an amount of 5 to 95 wt.-% in respect to the total amount of (A) and (B).

34. (canceled)

35. A mixture of hydrocarbons and water comprising a composition according to claim 1, wherein the mixture has a reduced tendency to form hydrocarbon hydrate agglomerates under hydrate forming conditions.

Description

EXAMPLES

[0183] Test Procedure 1: Evaluation of Hydrate Inhibitor Formulations.

[0184] To a 100 mL stainless steel reactor, attached to thermostat and a liquid handling system, dodecane (10 mL), brine (20 mL of 5% NaCl, density of 1.07 g/cm.sup.3 at 25° C.), and the anti-agglomerant formulation were added at 30° C. The reactor was pressurized to 95 bar with Erdgas H (see Table 1 for composition). The stirrer speed was adjusted to 1000 rpm for 1 min to saturate the liquid with gas. Subsequently the stirrer speed was reduced to 200 rpm, and a temperature setting of −10° C. was initiated. Monitoring the internal temperature of the reactor showed a characteristic exotherm indicative of hydrate formation below a threshold temperature. If the exotherm was accompanied by a prolonged increase in stirrer power uptake this was indicative of agglomeration, signifying a failure. If the stirrer power remained constant or following an increase returned to the original baseline, agglomeration was prevented; indicating a pass.

[0185] For evaluation of their hydrate inhibitor performance, the testing was started with 0.3 wt.-% of the hydrate inhibitor, formulated as a 60% active solution in methanol. If samples failed at this dose rate, they were labelled as >0.3 wt.-% minimum effective dose (MED) and were not tested further. If samples initially tested at 0.3 wt.-% passed, they were sequentially and incrementally reduced in dose rate by 0.05 wt.-% each time until a dose rate was used that failed. When that occurred, the last passing dose rate was input into the Table (4) as the Minimum Effective Dose (MED).

TABLE-US-00001 TABLE 1 Erdgas H gas composition Component Name Chemical Symbol Amount (mol-%) Nitrogen N.sub.2 0.14 Carbon Dioxide CO.sub.2 0.00 Methane C.sub.1 87.56 Ethane C.sub.2 7.60 Propane C.sub.3 3.00 i-Butane i-C.sub.4 0.50 n-Butane n-C.sub.4 0.80 i-Pentane i-C.sub.5 0.20 n-Pentane n-C.sub.5 0.20

[0186] Test Procedure 2: Water Drop Testing

[0187] Into a graduated 100 mL cylinder with conical bottom (typically used for emulsion testing), 50 mL of oil and 50 mL of water were charged. The water was 6% brine (using NaCI) and the oil was a medium crude from the Gulf of Mexico. To the 100 mL of total fluids 1 wt.-% in respect to the aqueous phase of a hydrate inhibitor (as a 60 wt.-% active formulation) were added. A dose rate of 1% was deliberately chosen to highlight the effect of the hydrate inhibitors on the water drop. The bottles were capped, shaken vigorously by hand, and allowed to stand at room temperature for 1 minute, at which point the amount of water that could be observed as a separate phase was recorded. This number was then multiplied by 2 to obtain the results shown in Table 4 as a percent of water present. A value of 100% means that all the water was observed as a separate phase. If less than 100% was observed, the remaining water was either within the oil or as part of a “rag layer” or emulsion layer.

[0188] For testing, gas hydrate inhibitor formulations were prepared by blending amphiphiles (A) according to table 2 and cationic surfactants (B) according to table 3 with the weight ratios according to table 4. For ease of handling, the formulations were adjusted to 60 wt.-% active content with methanol.

[0189] These formulations were tested for their minimum dosage rate for hydrate inhibition according to test procedure 1. The minimum dosage rates for a pass given in table 4 refer to the required minimum dosage of active ingredient.

TABLE-US-00002 TABLE 2 Characterization of tested amphiphiles A) Residue A1 A2 L —N(R.sup.7)—C(═O)—(CH.sub.2).sub.2—N(R.sup.6)—(CH.sub.2).sub.t— —C(═O)—N(R.sup.6)—(CH.sub.2).sub.t— R.sup.1 n-butyl n-butyl R.sup.2 n-butyl n-butyl R.sup.3 C.sub.2H.sub.5 H R.sup.5 C.sub.12H.sub.25 coconut cut R.sup.6 H H R.sup.7 H — t 3 3 X.sup.− ethyl sulfate acrylate Residue A3 A4 L —CH(OH)—CH.sub.2—N(R.sup.6)—(CH.sub.2).sub.t— [00010] R.sup.1 n-butyl methyl R.sup.2 n-butyl methyl R.sup.3 H —CH.sub.2—CH(OH)—CH.sub.3 R.sup.5 C.sub.10H.sub.21 C.sub.12H.sub.25 R.sup.6 H — R.sup.7 — — t 3 3 X.sup.− methyl sulfate acetate Coconut cut comprises as main components 51 wt.-% C.sub.12H.sub.25, and 16 wt.-% C.sub.14H.sub.29.

TABLE-US-00003 TABLE 3 Characterization of tested cationic surfactants B) having general formula N.sup.+(R.sup.11)(R.sup.12)(R.sup.19)(R.sup.20) Y.sup.− R.sup.11 R.sup.12 R.sup.19 R.sup.20 anion Y.sup.− B1 C.sub.10H.sub.21 C.sub.10H.sub.21 CH.sub.3 CH.sub.3 Cl.sup.− B2 C.sub.10H.sub.21 C.sub.10H.sub.21 CH.sub.3 CH.sub.3 Br.sup.− B3 C.sub.8H.sub.17 C.sub.8H.sub.17 CH.sub.3 CH.sub.3 Cl.sup.− B4 C.sub.12H.sub.25 C.sub.12H.sub.25 CH.sub.3 CH.sub.3 Cl.sup.− B5 coco alkyl coco alkyl CH.sub.3 CH.sub.3 Cl.sup.− B6 C.sub.10H.sub.21 C.sub.12H.sub.25 CH.sub.3 CH.sub.3 Cl.sup.− B7 C.sub.14H.sub.29 C.sub.14H.sub.29 CH.sub.3 CH.sub.3 Br.sup.− B8 C.sub.16H.sub.33 C.sub.16H.sub.33 CH.sub.3 CH.sub.3 Cl.sup.− B9 iso-C.sub.9H.sub.19 iso-C.sub.9H.sub.19 CH.sub.3 CH.sub.3 Cl.sup.− B10 (comp.) CH.sub.3 C.sub.18H.sub.37 CH.sub.3 CH.sub.3 Cl.sup.− B11 (comp.) C.sub.4H.sub.9 C.sub.12H.sub.25 CH.sub.3 CH.sub.3 Br.sup.− B12 (comp.) C.sub.4H.sub.9 C.sub.16H.sub.33 CH.sub.3 CH.sub.3 Br.sup.− B13 (comp.) C.sub.4H.sub.9 C.sub.18H.sub.37 CH.sub.3 CH.sub.3 Br.sup.− B14 (comp.) C.sub.4H.sub.9 C.sub.12H.sub.25 C.sub.4H.sub.9 C.sub.4H.sub.9 Br.sup.− B15 (comp.) C.sub.12H.sub.25 C.sub.12H.sub.25 CH.sub.3 H Cl.sup.− Coco alkyl comprises as main components 51 wt.-% C.sub.12H.sub.25, and 16 wt.-% C.sub.14H.sub.29.

TABLE-US-00004 TABLE 4a Results from autoclave testing (components testing; comparative) Gas hydrate inhibitor (wt.-% active) MED water drop Example comp. A comp. B (wt.-%) (%)  1 (comp.) A1 (100) — 0.30 80  2 (comp.) A2 (100) — 0.30 84  3 (comp.) A3 (100) — 0.30 76  4 (comp.) A4 (100) — 0.30 74  5 (comp.) — B1 (100)  >0.30.sup.(a) 70  6 (comp.) — B2 (100)  >0.30.sup.(a) 70  7 (comp.) — B3 (100)  >0.30.sup.(a) 74  8 (comp.) — B4 (100)  >0.30.sup.(a) 72  9 (comp.) — B5 (100)  >0.30.sup.(a) 66 10 (comp.) — B6 (100)  >0.30.sup.(a) 66 11 (comp.) — B7 (100)  >0.30.sup.(a) 72 12 (comp.) — B8 (100)  >0.30.sup.(a) 72 13 (comp.) — B9 (100)  >0.30.sup.(a) 70 14 (comp.) — B10 (100) >0.30.sup.(a) 76 15 (comp.) — B11 (100) 0.30 70 16 (comp.) — B12 (100) >0.30.sup.(a) 76 17 (comp.) — B13 (100) >0.30.sup.(a) 70 18 (comp.) — B14 (100) 0.30 78 19 (comp.) — B15 (100) >0.30.sup.(a) 70

TABLE-US-00005 TABLE 4b Results from autoclave testing (formulations containing A1) Gas hydrate inhibitor (wt.-% active) MED water drop Example comp. A comp. B (wt.-%) (%) 20 A1 (50.0) B1 (50.0)  0.05 94 21 A1 (71.4) B1 (28.6)  0.10 92 22 A1 (50.0) B2 (50.0)  0.05 94 23 A1 (33.0) B2 (67.0)  0.10 92 24 A1 (50.0) B3 (50.0)  0.15 92 25 A1 (71.4) B3 (28.6)  0.10 94 26 A1 (50.0) B4 (50.0)  0.15 90 27 A1 (71.4) B4 (28.6)  0.15 92 28 A1 (50.0) B5 (50.0)  0.15 94 29 A1 (71.4) B5 (28.6)  0.15 90 30 A1 (50.0) B7 (50.0)  0.15 88 31 A1 (71.4) B7 (28.6)  0.15 90 32 A1 (50.0) B8 (50.0)  0.15 88 33 A1 (71.4) B8 (28.6)  0.15 88 34 (comp.) A1 (50.0) B10 (50.0) 0.20 84 35 (comp.) A1 (71.4) B10 (28.6) 0.20 86 36 (comp.) A1 (50.0) B13 (50.0) 0.20 84 37 (comp.) A1 (71.4) B13 (28.6) 0.20 84 38 (comp.) A1 (50.0) B14 (50.0) 0.20 82 39 (comp.) A1 (71.4) B14 (28.6) 0.20 80

TABLE-US-00006 TABLE 4c Results from autoclave testing (formulations containing A2) Gas hydrate inhibitor (wt.-% active) MED water drop Example comp. A comp. B (wt.-%) (%) 40 A2 (50.0) B1 (50.0)  0.05 96 41 A2 (71.4) B1 (28.6)  0.05 100 42 A2 (50.0) B3 (50.0)  0.10 96 43 A2 (71.4) B3 (28.6)  0.05 98 44 A2 (50.0) B4 (50.0)  0.10 96 45 A2 (71.4) B4 (28.6)  0.15 100 46 A2 (25.0) B3 (75.0)  0.15 96 47 A2 (50.0) B5 (50.0)  0.10 94 48 A2 (71.4) B5 (28.6)  0.10 98 49 A2 (50.0) B7 (50.0)  0.15 96 50 A2 (71.4) B7 (28.6)  0.15 96 51 A2 (50.0) B8 (50.0)  0.15 96 52 A2 (71.4) B8 (28.6)  0.15 94 53 A2 (50.0) B9 (50.0)  0.15 94 54 A2 (71.4) B9 (28.6)  0.15 98 55 (comp.) A2 (50.0) B10 (50.0) 0.20 92 56 (comp.) A2 (71.4) B10 (28.6) 0.20 92 57 (comp.) A2 (25.0) B10 (75.0) 0.20 82 58 (comp.) A2 (50.0) B11 (50.0) 0.20 90 59 (comp.) A2 (71.4) B11 (28.6) 0.20 88 60 (comp.) A2 (50.0) B12 (50.0) 0.20 88 61 (comp.) A2 (71.4) B12 (28.6) 0.20 86 62 (comp.) A2 (50.0) B15 (50.0) 0.30 92 63 (comp.) A2 (71.4) B15 (28.6) 0.25 92

TABLE-US-00007 TABLE 4d Results from autoclave testing (formulations containing A3) Gas hydrate inhibitor (wt.-% active) MED water drop Example comp. A comp. B (wt.-%) (%) 64 A3 (50.0) B1 (50.0)  0.10 94 65 A3 (71.4) B1 (28.6)  0.10 96 66 A3 (28.6) B2 (71.4)  0.15 92 67 A3 (71.4) B2 (28.6)  0.10 94 68 A3 (50.0) B3 (50.0)  0.10 96 69 A3 (71.4) B3 (28.6)  0.15 96 70 A3 (50.0) B4 (50.0)  0.10 90 71 A3 (71.4) B4 (28.6)  0.15 94 72 A3 (50.0) B5 (50.0)  0.15 92 73 A3 (71.4) B5 (28.6)  0.15 96 74 A3 (50.0) B7 (50.0)  0.15 94 75 A3 (71.4) B7 (28.6)  0.15 94 76 A3 (50.0) B8 (50.0)  0.15 92 77 A3 (71.4) B8 (28.6)  0.15 92 78 (comp.) A3 (71.4) B10 (28.6) 0.25 86 79 (comp.) A3 (50.0) B10 (50.0) 0.30 88 80 (comp.) A3 (28.6) B10 (71.4) 0.25 82 81 (comp.) A3 (50.0) B13 (50.0) 0.20 88 82 (comp.) A3 (71.4) B13 (28.6) 0.20 88 83 (comp.) A3 (50.0) B14 (50.0) 0.20 82 84 (comp.) A3 (71.4) B14 (28.6) 0.20 84

TABLE-US-00008 TABLE 4e Results from autoclave testing (formulations containing A4) Gas hydrate inhibitor (wt.-% active) MED water drop Example comp. A comp. B (wt.-%) (%)  85 A4 (50.0) B1 (50.0)  0.05 92  86 A4 (71.4) B1 (28.6)  0.05 96  87 A4 (50.0) B2 (50.0)  0.05 94  88 A4 (71.4) B2 (28.6)  0.05 96  89 A4 (50.0) B3 (50.0)  0.10 96  90 A4 (71.4) B3 (28.6)  0.10 96  91 A4 (50.0) B4 (50.0)  0.10 94  92 A4 (71.4) B4 (28.6)  0.10 98  93 A4 (50.0) B5 (50.0)  0.10 90  94 A4 (71.4) B5 (28.6)  0.15 92  95 A4 (50.0) B7 (50.0)  0.15 90  96 A4 (71.4) B7 (28.6)  0.15 90  97 A4 (50.0) B8 (50.0)  0.15 90  98 A4 (71.4) B8 (28.6)  0.15 96  99 (comp.) A4 (50.0) B10 (50.0) 0.20 88 100 (comp.) A4 (71.4) B10 (28.6) 0.20 86 101 (comp.) A4 (50.0) B12 (50.0) 0.20 80 102 (comp.) A4 (71.4) B12 (28.6) 0.20 82 103 (comp.) A4 (50.0) B14 (50.0) 0.20 84 104 (comp.) A4 (71.4) B14 (28.6) 0.20 84 .sup.(a)>0.30 wt-% means it did not pass at 0.30 wt-% dose rate and was not tested at higher concentration.