Viscosity enhancers for viscoelastic surfactant stimulation fluids
View Patent ↗Piezoelectric crystal particles (which include pyroelectric crystal particles) enhance the viscosity of aqueous fluids that have increased viscosity due to the presence of viscoelastic surfactants (VESs). In one non-limiting theory, when the fluid containing the viscosity enhancers is heated and/or placed under pressure, the particles develop surface charges that associate, link, connect, or relate the VES micelles thereby increasing the viscosity of the fluid. The higher fluid viscosity is beneficial to crack the formation rock during a fracturing operation, reduce fluid leakoff, and carry high loading proppants to maintain the high conductivity of fractures.
1. An aqueous viscoelastic treating fluid comprising:
an aqueous base fluid;
a viscoelastic surfactant (VES) gelling agent; and
a viscosity enhancer selected from the group consisting of berlinite (AlPO 4 ), lithium tantalate (LiTaO 3 ), gallium orthophosphate (GaPO 4 ), BaTiO 3 , SrTiO 3 , PbZrTiO 3 , KNbO 3 , LiNbO 3 , BiFeO 3 , sodium tungstate, Ba 2 NaNb 5 O 5 , Pb 2 KNb 5 O 15 , potassium sodium tartrate, tourmaline, topaz and mixtures thereof, where the viscosity enhancer has a particle size ranging from about 1 nanometer to about 2 microns.
2. The aqueous viscoelastic treating fluid of claim 1 where the aqueous base fluid is brine.
3. The aqueous viscoelastic treating fluid of claim 1 where the viscosity enhancer is present in an amount effective to improve viscosity of the fluid as compared with an identical fluid absent the viscosity enhancer.
4. The aqueous viscoelastic treating fluid of claim 1 where the effective amount of the viscosity enhancer ranges from about 0.1 to about 500 pptg (about 0.012 to about 60 kg/m 3 ) based on aqueous viscoelastic treating fluid.
5. An aqueous viscoelastic treating fluid comprising:
an aqueous brine base fluid;
a viscoelastic surfactant (VES) gelling agent; and
a viscosity enhancer selected from the group consisting of pyroelectric particles, piezoelectric particles, and mixtures thereof, where the viscosity enhancer is present in an amount effective to improve viscosity of the fluid as compared with an identical fluid absent the viscosity enhancer, where the viscosity enhancer has a particle size ranging from about 1 nanometer to about 2 microns, where viscosity enhancer is selected from the group consisting of berlinite (AlPO 4 ), lithium tantalate (LiTaO 3 ), gallium orthophosphate (GaPO 4 ), BaTiO 3 , SrTiO 3 , PbZrTiO 3 , KNbO 3 , LiNbO 3 , BiFeO 3 sodium tungstate, Ba 2 NaNb 5 O 5 , Pb 2 KNb 5 O 15 , potassium sodium tartrate, tourmaline, topaz and mixtures thereof.
6. An aqueous viscoelastic treating fluid comprising:
an aqueous brine base fluid;
a viscoelastic surfactant (VES) gelling agent; and
from about 0.1 to about 500 pptg (about 0.012 to about 60 kg/m 3 ) based on the total aqueous viscoelastic treating fluid of a viscosity enhancer selected from the group consisting of berlinite (AlPO 4 ), lithium tantalate (LiTaO 3 ), gallium orthophosphate (GaPO 4 ), BaTiO 3 , SrTiO 3 , PbZrTiO 3 , KNbO 3 , LiNbO 3 , BiFeO 3 , sodium tungstate, Ba 2 NaNb 5 O 5 , Pb 2 KNb 5 O 15 , potassium sodium tartrate, tourmaline, topaz and mixtures thereof, where the viscosity enhancer has a particle size ranging from about 1 nanometer to about 2 microns.