Additives for inhibiting gas hydrate formation
AssigneesClariant GmbH, RF-Rogaland Research
InventorsPeter Klug, Malcolm Kelland
Life of this patent
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Abstract
An additive for inhibiting the formation of gas hydrates in connection with hydrocarbon production and transportation comprising the water-soluble polymers comprising structural elements of the formula wherein each R is independently H or C1-C5-alkyl; X is H, an alkaline or earth alkaline metal or a quaternary ammonium group; R1 is H or C1-C18-alkyl; and R2 is C1-C18-alkyl; and wherein the alkyl groups represented by R1 and R2 optionally carry a hydroxy or amino substituent; and, optionally, a minor proportion of structural elements of the formula wherein R, R1, R2 and X may have the meaning as above, and Alk is a C1-C5-alkylene chain.
Claims20
A method of use for inhibiting the formation of gas hydrates in pipes containing water and gas or oil, comprising incorporating from 0.05 to 5% by weight based on the amount of said water present, an additive in said pipes, said additive comprising a water-soluble polymer or copolymer comprising structural units of the formula
- wherein
- each R is independently H or C1-C5-alkyl;
- X is H, an alkaline or earth alkaline metal or a quaternary ammonium group;
- R1 is H or C1-C18-alkyl;
- and
- R2 is C1-C18-alkyl;
- and wherein the alkyl groups represented by R1 and R2 optionally carry a hydroxy or amino substituent;
- and optionally said polymer contains a minor proportion of structural units of the formula (II)
- wherein said polymer comprising (I) and optionally (II) has a molecular weight of from 500 to 2,000,000, R, R1, R2 and X have the meaning as above, and Alk is a C1-C5-alkylene chain, and said polymer further comprises more than one structural unit from different monomers of formula (I) and optionally, (II).
A method of inhibiting gas hydrate formation, in a system for oil and gas drilling, production and/or transportation, which comprises adding to the system an additive comprising a water soluble polymer or copolymer comprising structural units of the formula
- wherein
- each R is independently H or C1-C5-alkyl;
- X is H, an alkaline or earth alkaline metal or a quartemnary ammonium group;
- R1 is H or C1-C18-alkyl;
- and
- R2 is C1-C18-alkyl;
- and wherein the alkyl groups represented by R1 and R2 optionally carry a hydroxy or amino substituent;
- and optionally said polymer contains a minor proportion of structural units of the formula
- wherein said polymer comprising (I) and optionally (II) has a molecular weight of from 500 to 2,000,000, R, R1, R2 and X have the meaning as above, and Alk is a C1-C5-alkylene chain,
- said additive is added in an amount of 0.01 to 2% by weight based on the water present in the system;
- and wherein said additive further comprises a synergist in combination with said polymer, and wherein the synergist is:
- a) a polymer or copolymer of N-vinylcaprolactam, N-vinylpyrrolidone, alkylated vinylpyrrolidone, acryloylpyrrolidine, or a polyamino acid,
- b) butoxyethanol or 2-butoxypropanol, or
- c) tetrabutylammonium salt, tetrapentylammonium salt, tributylamine oxide, tripentyl amine oxide, a compound containing a di- and/or trialkylammonium group, wherein the alkyl is butyl or pentyl, or a zwitterionic compound having at least one butyl or pentyl group on the quaternary ammonium nitrogen atom.
Dependencies are inferred from the claim text.