Patent ID: 8124570

Claim:
A viscoelastic fluid, comprising: one or more cationic surfactants, wherein the one or more cationic surfactants is selected from the group consisting of methylpolyoxyethylene cocoalkylammonium chloride, isotridecyloxypropyl polyoxyethylene methyl ammonium chloride, polyoxyethylene cocoalkylamines, polyoxyethylene tallowalkylamines, and polyoxyethylene oleylamines; one or more anionic surfactants having alkyl chains of about 6 to about 18 carbon atoms with at least one negatively charged moiety; one or more zwitterionic surfactants and/or one or more amphoteric surfactants; and water; wherein the one or more cationic surfactants is selected from the group consisting of i) quaternary salts having the following structural formula: wherein R 1 is a hydrophobic moiety of alkyl, alkylarylalkyl, alkoxyalkyl, alkylaminoalkyl or alkylamidoalkyl, wherein R 1 has from about 18 to about 30 carbon atoms and may be branched or straight-chained and saturated or unsaturated; R 2 , R 3 , and R 5 are, independently, selected from the group consisting of an aliphatic moiety having from 1 to about 30 carbon atoms and an aromatic moiety having from 7 to about 30 carbon atoms; the aliphatic moiety being branched or straight-chained and saturated or unsaturated; wherein X is a counter-anion; ii) amines having the following structural formula: wherein R 1 , R 2 and R 3 are the same as defined above; iii) amine oxides having the following structural formula: wherein R 1 , R 2 and R 3 are as defined above; and iv) combinations thereof; wherein the one or more zwitterionic surfactants has the following structural formula: wherein R 1 , R 2 , and R 3 are as described above; R 4 is a hydrocarbyl radical with a chain length 1 to 4; and wherein the one or more amphoteric surfactants has the following structural formula: wherein R 1 , R 2 , and R 4 are as described above.