Patent ID: 7427583
Filing Date: 2008-09-23
Classification: C09K

Abstract:
1. Aqueous viscoelastic fracturing fluid for use in the recovery of hydrocarbons, comprising a viscoelastic surfactant and a hydrophobically-modified polymer, wherein the surfactant comprises a head group and a hydrophobic tail and is of the following formula: where R is the hydrophobic tail of said viscoelastic surfactant, which is a fully or partially saturated, linear or branched, hydrocarbon chain of at least 18 carbon atoms; X is a degradable acetal, amide, ether or ester bond; Y is a spacer group, formed by a short fully or partially saturated hydrocarbon chain of at least one carbon atom; and Z is the head group of the surfactant which can be —NR 1 R 2 R 3 + , —SO 3 − , —COO − or —N + R 1 R 2 R 3 —COO − where R 1 , R 2 and R 3 are each independently hydrogen or a linear or branched saturated aliphatic chain of at least one carbon atom and wherein the concentration of the hydrophobically-modified polymer is comprised between, approximately, its overlap concentration c* and, approximately, its entanglement concentration c