Method for treating and sealing piezoelectric tuning forks
Disclosed is an apparatus for estimating a property of a fluid. The apparatus includes: a piezoelectric resonator configured to be disposed in the fluid; an electrode embedded in the piezoelectric resonator and included in a resonator circuit configured to output an electrical signal related to the property; a discontinuity defined by a surface of the piezoelectric resonator, the discontinuity altering an impedance of the resonator circuit if a high-dielectric fluid or a conductive fluid is disposed in the discontinuity; and an insulating material disposed in the discontinuity.
1. An apparatus for estimating a property of a fluid, the apparatus comprising:
a piezoelectric resonator configured to be disposed in the fluid;
an electrode embedded in the piezoelectric resonator and included in a resonator circuit configured to output an electrical signal related to the property;
a discontinuity defined by a surface of the piezoelectric resonator, the discontinuity altering an impedance of the resonator circuit if a high-dielectric fluid or a conductive fluid is disposed in the discontinuity; and
an insulating material disposed in the discontinuity;
wherein the insulating material is a liquid configured to wet to the piezoelectric resonator better than water or oil.
2. The apparatus of claim 1 , wherein the insulating material comprises a low dielectric constant.
3. The apparatus of claim 1 , wherein the piezoelectric resonator is made of lithium niobate.
4. The apparatus of claim 1 , wherein the insulating material comprises a perfluorinated polyether.
5. The apparatus of claim 1 , wherein the property comprises at least one of density and viscosity.
6. The apparatus of claim 1 , wherein the discontinuity comprises at least one of a crack, a fissure, and a depression.
7. The apparatus of claim 6 , wherein the discontinuity penetrates to the electrode.
8. The apparatus of claim 1 , wherein the piezoelectric resonator comprises a tuning fork, wherein the tuning fork comprises a first tuning fork section having a first surface and a second tuning fork section having a second surface, wherein the electrode is embedded between the first section and the second section, and wherein the tuning fork further comprises a bond between the first surface and the second surface.
9. The apparatus of claim 8 , wherein the bond comprises the discontinuity.
10. The apparatus of claim 1 , further comprising:
a carrier configured to be conveyed through a borehole penetrating the earth;
wherein the piezoelectric resonator is disposed at the carrier.
11. The apparatus of claim 10 , wherein the fluid is a downhole fluid.
12. The apparatus of claim 10 , wherein the carrier comprises at least one of a wireline, a slickline, a drill string, and coiled tubing.
13. A method for estimating a property of a fluid, the method comprising:
disposing a piezoelectric resonator in a fluid wherein an electrode included in a resonator circuit is embedded in the piezoelectric resonator, the piezoelectric resonator comprising a discontinuity configured to alter an impedance of the resonator circuit if a high-dielectric fluid or a conductive fluid is disposed in the discontinuity;
using the resonator circuit to resonate the piezoelectric resonator; and
obtaining a signal related to the property from the resonator circuit;
wherein an insulating material is disposed in the discontinuity, the insulating material being a liquid configured to wet to the piezoelectric resonator better than water or oil.
14. The method of claim 13 , wherein the piezoelectric resonator is made of lithium niobate.
15. The method of claim 13 , wherein the insulating material comprises a low dielectric constant.
16. The method of claim 13 , wherein the piezoelectric resonator comprises a tuning fork, wherein the tuning fork comprises a first tuning fork section having a first surface and a second tuning fork section having a second surface, wherein the electrode is embedded between the first section and the second section, and wherein the tuning fork further comprises a bond between the first surface and the second surface.
17. The method of claim 16 , wherein the bond comprises the discontinuity.
18. A method for producing a piezoelectric resonator, the method comprising: disposing an insulating material in a discontinuity in a surface of the piezoelectric resonator, wherein the discontinuity is defined by a surface of the piezoelectric resonator, the discontinuity altering an impedance of the resonator circuit if a high-dielectric fluid or a conductive fluid is disposed in the discontinuity; and removing the insulating material from a surface of the piezoelectric resonator not intended to be sealed with the insulating material; wherein the insulating material is a liquid configured to wet to the piezoelectric resonator better than water or oil.
19. The method of claim 18 , further comprising cleaning the discontinuity prior to the disposing.
20. The method of claim 18 , wherein the insulating material comprises a perfluorinated polyether.
21. A piezoelectric resonator for estimating a property of a fluid, the resonator comprising:
an electrode embedded in piezoelectric material and configured to output a signal responsive to the property; and
an insulating material disposed in a discontinuity defined by a surface of the piezoelectric material, the discontinuity altering the signal if a high-dielectric fluid or a conductive fluid is disposed in the discontinuity without the insulating material in the discontinuity;
wherein the insulating material is a liquid configured to wet to the piezoelectric resonator better than water or oil.