Composition that can be used to delay the formation of gas hydrates
The present invention relates to a composition comprising: at least one co-polymer of which at least one of the repeating units comprises at least one amide function; and at least one polyether having a molecular weight (M W ) greater than 60 g·mol −1 . The invention also relates to the use of said composition for delaying, or even preventing, the formation of gas hydrates, in particular in a method for extracting oil and/or gas and/or condensates, as well as to the method for delaying, or even preventing, the formation and/or agglomeration of gas hydrates, using a composition as defined above.
1. A composition comprising:
a) between 5% and 40% by weight with respect to the total weight of the composition of at least one copolymer obtained by polymerization of vinylpyrrolidone (VP) and vinylcaprolactam (VCap);
b) between 1% and 30% by weight, with respect to the total weight of the composition of at least one polyether with a weight-average molecular weight (Mw) of greater than 260 g.mol −1 that is chosen from among polyoxymethylene glycol, polymethylene glycol, polyethylene glycol, polypropylene glycol, polybutylè ne glycol, trimethylolpropane triglycidyl ether, neopentyl glycol diglycidyl ether, poly (ethylene glycol) glycidyl ether, poly (propylene glycol) glycidyl ether, poly (ethylene glycol) diglycidyl ether, poly (propylene glycol) diglycidyl ether, poly (ethylene glycol) triglycidyl ether, poly (propylene glycol) triglycidyl ether, poly (ethylene glycol) tetraglycidyl ether, poly (propylene glycol) tetraglycidyl ether, glycerol propoxylate triglycidyl ether, poly (ethylene glycol) methyl ether, poly (ethylene glycol) methyl ether acetate, polyethylene glycol dimethyl ether, le trimethylolpropane ethoxylate, methoxypolyethylene glycol, glycerolèthoxylate, 4-nonylphenyl-polyethylene glycol, glycerol propoxylate, pentaerythritol triacrylate, pentaerythritol propoxylate, and pentaerythritol butoxylate, and
c) optionally at least one organic solvent.
2. The composition as claimed in claim 1 , wherein the at least one organic solvent is an alkyl alcohol comprising from 1 to 4 carbon atoms, a glycol ether or mixtures thereof.
3. A process for preventing, limiting or delaying formation and/or agglomeration of gas hydrates, comprising a step of adding the composition as defined in claim 1 to a mixture having a composition capable of forming hydrates.
4. The process as claimed in claim 3 , wherein the composition of claim 1 is added in an amount between 0.1% and 10% by weight, with respect to the total weight of an aqueous phase of a fluid capable of forming hydrates.
5. The process as claimed in claim 4 , wherein the composition is introduced into the fluid continuously, discontinuously, regularly or irregularly, or temporarily, in one or more portions.
6. The process as claimed in claim 4 , wherein the fluid treated with the composition is a drilling mud or a completion fluid or a fluid extracted from the subsoil.
7. The composition as claimed in claim 1 , wherein the VCap/VP ratio by weight is between 75/25 and 50/50.
8. The composition as claimed in claim 1 , wherein the VCap/VP ratio by weight is between 60/40 and 50/50.
9. The composition as claimed in claim 1 , wherein the at least one organic solvent is present.
10. The composition as claimed in claim 9 , wherein the at least one organic solvent is chosen from alkyl alcohols comprising from 1 to 4 carbon atoms, glycol ethers and mixtures thereof.