Methods of fracturing subterranean formations

A method for fracturing a subterranean formation comprising:

• (a) providing an aqueous viscoelastic surfactant-based fracturing fluid, including a thickener comprising:
• a solution medium selected from the group consisting of freshwater, seawater, a freshwater/seawater mixture;
• an amount of a salt sufficient to provide formation stability;
• at least one thickener in the fluid, the thickener being at least one member selected from the group consisting of
• (i) an amine corresponding to the formula
• wherein R1 is at least about a C16 to about a C22 group which may be aliphatic or aromatic, or some combination of the two, branched or straight chained and which may be saturated or unsaturated, R2 and R3 are each independently, hydrogen or a C1 to about C6 aliphatic group which can be branched or straight chained, saturated or unsaturated and which may be substituted with a group that renders the R2 or R3 group more hydrophilic, or
• (ii) an amine salt corresponding to the formula
• wherein R1, R2 and R3 are the same as defined herein and X— is an anion, or
• (iii) a quaternary ammonium salt of an amine corresponding to the formula
• wherein R1, R2, R3 and X— are the same as defined herein and R4 constitutes a group which has been previously set forth for R3, and none of R1, R2, R3 or R4 are hydrogen, and further wherein the R2, R3 and R4 groups of the amine salt and quaternary ammonium salt may form a 5- or 6-member heterocyclic structure, wherein said structure includes the nitrogen atom of the amine;
• (b) generating a viscous fluid comprising micelles;
• (c) pumping the viscous fluid comprising micelles through a wellbore and into a formation at a pressure sufficient to fracture said formation;
• and
• (d) structurally altering the micelles within the fluid in the hydrocarbon zone, thereby decreasing the viscosity of the fluid in contact with hydrocarbon.

A method for acidizing a subterranean formation comprising:

• (a) providing an aqueous viscoelastic surfactant-based fluid, including a thickener comprising:
• a solution medium selected from the group consisting of freshwater, seawater, a freshwater/seawater mixture;
• an amount of a salt sufficient to provide formation stability;
• at least one thickener in the fluid, the thickener being at least one member selected from the group consisting of
• an amine corresponding to the formula
• wherein R1 is at least about a C16 to about a C22 aromatic or aliphatic group or some combination of both, and which may be branched or straight chained and which may be saturated or unsaturated, R2 and R3 are each independently, hydrogen or a C1 to about C6 aliphatic group which can be branched or straight chained, saturated or unsaturated and which may be substituted with a group that renders the R2 or R3 group more hydrophilic, or
• the amine salt corresponding to the formula
• wherein R1, R2 and R3 are the same as defined herein and X— is an anion, or
• a quaternary ammonium salt of the amine corresponding to the formula
• wherein R1, R2, R3 and X— are the same as defined herein and R4 constitutes a group which has been previously set forth for R3, and none of R1, R2, R3 or R4 are hydrogen, and further wherein the R2, R3 and R4 groups of the amine salt and quaternary ammonium salt may form a 5- or 6-member heterocyclic structure, wherein said structure includes the nitrogen atom of the amine;
• (b) generating a viscous fluid comprising micelles;
• and
• (c) pumping the viscous fluid comprising micelles through a wellbore and into said formation.