Patent ID: 7410934

Claim:
An aqueous viscoelastic fluid for use in the recovery of hydrocarbons, comprising: a monomer, a dimer or oligomer of an anionic or cationic viscoelastic surfactant able to form a viscoelastic gel under downhole conditions, said anionic or cationic surfactant comprising a hydrophobic tail and a hydrophilic head, and being of the following formulae: R—X—Y-Z where R is the hydrophobic tail of the surfactant, Z is the hydrophilic head of the surfactant, said hydrophilic head group being charged, X is a stabilising group and Y is a linear, saturated or unsaturated, hydrocarbon chain of 1, 2 or 3 carbon atoms or a branched, saturated or unsaturated hydrocarbon chain wherein the main chain is of 1, 2 or 3 carbon atoms, and wherein: said anionic or cationic viscoelastic surfactant is cleavable into a subcompound; said subcompound is a breaker of viscoelastic gels; said breaker subcompound comprises one of a long chain alcohol, a long chain amine and a long chain carboxylic acid, where the lone chain of the long chain alcohol, the long chain amine and the long chain carboxylic acid comprises 18 or more carbon atoms; and the cleaving of said anionic or cationic viscoelastic surfactant into said breaker subcompound provides for amplification of degradation of the viscoelastic gel formed by said anionic or cationic viscoelastic surfactant.