Nano-dispersion well servicing fluid containing a pH adjuster
View Patent ↗A nano-dispersion well servicing fluid is disclosed. The well servicing fluid is formulated with components comprising: nanoparticles comprising at least one material chosen from aluminum oxides, aluminum hydroxides, aluminum hydroxyoxides, zirconium oxides, zirconium hydroxides, zirconium hydroxyoxides, wherein the concentration of nanoparticles is greater than 0.5% by weight based on the total weight of the nano-dispersion well servicing fluid. The well servicing fluid also comprises an aqueous base continuous phase. Methods of employing the nano-dispersion to service a wellbore are also disclosed.
1. A nano-dispersion well servicing fluid in a wellbore, the fluid being formulated with components comprising:
nanoparticles comprising at least one material chosen from aluminum oxides, aluminum hydroxides, aluminum hydroxyoxides, zirconium oxides, zirconium hydroxides, zirconium hydroxyoxides, the concentration of nanoparticles being greater than 0.5% by weight based on the total weight of the nano-dispersion well servicing fluid;
an aqueous base continuous phase, the nanoparticles forming a dispersion in the aqueous base continuous phase, the nanoparticles having a crystallized size of 100 nm or less in diameter prior to being dispersed, and the nanoparticles carrying a charge resulting in a Zeta potential in the nano-dispersion well servicing fluid; and
a pH adjuster configured to decrease the Zeta potential of the nano-dispersion well servicing fluid in the wellbore closer to zero and thereby to increase viscosity, the nano-dispersion well servicing fluid exhibiting a viscosity greater than would be exhibited without the pH adjuster.
2. The fluid of claim 1 , wherein the concentration of nanoparticles ranges from about 2% to about 20% by weight based on the total weight of the nano-dispersion well servicing fluid.
3. The fluid of claim 1 , wherein the fluid does not comprise a viscoelastic surfactant gelling agent in an amount effective to significantly increase the viscosity of the fluid.
4. The fluid of claim 1 , wherein the nanoparticles comprise more than 50 wt. % boehmite.
5. The fluid of claim 1 , wherein the pH adjuster decreases Zeta potential by increasing pH.
6. The fluid of claim 1 , having a Zeta potential ranging from about 0 to about 50.
7. The fluid of claim 1 , having a pH ranging from about 2 to about 14.
8. The fluid of claim 1 , further comprising at least one delayed compound chosen from pH adjusters, surfactants, and esters configured to increase Zeta potential after a delay and thereby to decrease viscosity.
9. The fluid of claim 1 , wherein the pH adjuster is chosen from NaOH, KOH, Ca(OH) 2 , sodium bicarbonate, potassium carbonate, and sodium carbonate.
10. The fluid of claim 8 , wherein the at least one delayed compound is an ester of polycarboxylic acid.
11. The fluid of claim 1 , further comprising proppant or gravel.
12. The fluid of claim 1 , wherein the continuous phase is a liquid chosen from fresh water, brine, and produced water.
13. The fluid of claim 12 , wherein the concentration of salt in the brine is 0.5% by weight or more, based on the total weight of the brine.
14. The fluid of claim 1 , wherein the fluid is formulated with at least one breaker.
15. The fluid of claim 1 , wherein the fluid is formulated with at least one additional compound chosen from water wetting surfactants, non-emulsifiers, additional viscosifying agents, surfactants, clay stabilization additives, scale dissolvers, biopolymer degradation additives, fluid loss control additives and high temperature stabilizers.
16. A nano-dispersion well servicing fluid in a wellbore, the fluid being formulated with components comprising:
nanoparticles comprising at least one material chosen from aluminum oxides, aluminum hydroxides, aluminum hydroxyoxides, zirconium oxides, zirconium hydroxides, zirconium hydroxyoxides, the concentration of nanoparticles being greater than 0.5% by weight based on the total weight of the nano-dispersion well servicing fluid;
an aqueous base continuous phase, the nanoparticles forming a dispersion in the aqueous base continuous phase, the nanoparticles having a crystallized size of 100 nm or less in diameter prior to being dispersed, and the nanoparticles carrying a charge resulting in a Zeta potential ranging from about 0 to about 50 in the nano-dispersion well servicing fluid; and
a pH adjuster configured to decrease the Zeta potential of the nano-dispersion well servicing fluid in the wellbore closer to zero by increasing pH and thereby to increase viscosity, the nano-dispersion well servicing fluid exhibiting a viscosity greater than would be exhibited without the pH adjuster; and
an ester configured to increase Zeta potential after a delay and thereby to decrease viscosity.
17. The fluid of claim 16 , wherein the pH adjuster is chosen from NaOH, KOH, Ca(OH) 2 , sodium bicarbonate, potassium carbonate, and sodium carbonate and the at least one delayed compound is an ester of polycarboxylic acid.
18. The fluid of claim 17 , further comprising proppant or gravel.