PEIZOELECTRIC GENERATOR PARTICULARLY FOR USE WITH WELLBORE DRILLING EQUIPMENT

• US 20090038848A1
• Filed: 08/09/2007
• Published: 02/12/2009
• Est. Priority Date: 08/09/2007
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Garcia-Osuna, Fernando
• Granted Patent: US 7,762,354 B2
• Time in Patent Office: Days
• US Class Current: 175/40
• CPC Class Codes: E21B 17/003 with electrically conducting or insulating means E21B17/028 and E21B17/023 take precedence
• CPC Class Codes: E21B 41/0085 Adaptations of electric power generating means for use in boreholes
• CPC Class Codes: H02N 2/181 Circuits; Control arrangements or methods
• CPC Class Codes: H02N 2/186 Vibration harvesters
• CPC Class Codes: H10N 30/503 having a non-rectangular cross-section in a plane orthogonal to the stacking direction, e.g. polygonal or circular in top view

Abstract

An electric power generator includes a conduit disposed in a wellbore penetrating subsurface formations and at least one piezoelectric transducer in contact with the conduit. The piezoelectric transducer is configured to undergo stress in response to vibration in the conduit. The transducer includes a plurality of piezoelectric crystals stacked in a thickness direction and each polarized in the thickness direction. The transducer comprises at least one of a composite rubber layer disposed between successive piezoelectric crystals, and at least one support at a longitudinal end of the transducer configured to cause the crystals to bend in response to vibration in the conduit.

Claims

1. An electric power generator, comprising:

a conduit disposed in a wellbore penetrating subsurface formations; and

at least one piezoelectric transducer in contact with the conduit, the piezoelectric transducer configured to undergo stress in response to vibration in the conduit, the transducer comprising a plurality of piezoelectric crystals stacked in a thickness direction and each polarized in the thickness direction, wherein the transducer comprises at least one of

a composite rubber layer disposed between successive piezoelectric crystals and at least one support at a longitudinal end of the transducer configured to cause the crystals to bend in response to vibration in the conduit.

2. The generator of claim 1 wherein the transducer comprises a reactive mass disposed on at least one of a longitudinal end thereof, and a longitudinal center thereof.

3. The generator of claim 1 wherein the conduit comprises a drill string.

4. The generator of claim 3 further comprising a plurality of circumferentially segmented piezoelectric transducers arranged about substantially an entire circumference of a chamber defined inside a sub forming part of the drill string.

5. The generator of claim 4 comprising a resilient tube extending along an interior of the chamber.

6. The generator of claim 4 wherein the circumferentially segmented piezoelectric transducers are configured to respond to axial drill string vibration induced during drilling.

7. The generator of claim 4 wherein the circumferentially segmented piezoelectric transducers are configured to respond to vibration induced by movement of fluid in an interior passage in the drill string.

8. The generator of claim 4 wherein the circumferentially segmented piezoelectric transducers are configured to respond to vibration induced by at least one of lateral vibration of the drill string and movement of fluid in an annular space between the drill string and a wall of the wellbore.

9. The generator of claim 3 further comprising an electromagnetic coupling in an end of the sub, the coupling configured to transmit electrical power generated by the at least one transducer to an adjacent component of the drill string by electromagnetic induction.

10. The generator of claim 1 wherein the at least one piezoelectric transducer has a resonant frequency selected to substantially match an expected frequency of vibration in the conduit.

11. The generator of claim 1 wherein the composite rubber layer comprises soft rubber adjacent to hard rubber.

12. The generator of claim 1 further comprising a spectral analyzer functionally coupled to an output of a vibration sensor, and a tunable resonance circuit functionally coupled between the output of the transducer and an electrical load, the tunable resonance circuit adjustable to cause a resonant frequency thereof to substantially match a frequency in the output of the vibration sensor.

13. The generator of claim 1 wherein the piezoelectric transducer comprises lead zirconate titanate.

14. The generator of claim 1 wherein the piezoelectric transducer comprises single crystal lead magnesium niobate-lead titanate.

15. The generator of claim 1 wherein the piezoelectric transducer comprises single crystal lead zirconate niobate-lead titanate.

16. A method for generating electrical power in a wellbore, comprising:

at least one of moving a conduit through a wellbore and moving fluid through the conduit in the wellbore; and

coupling vibrations induced in the conduit to a piezoelectric transducer, the vibrations induced by at least one of lateral vibration thereof, movement of fluid therethrough, movement of fluid outside thereof, and operation of a drill bit at a lower end thereof, wherein the transducer includes a plurality of piezoelectric crystals stacked in a thickness direction and each polarized in the thickness direction, and at least one of a composite rubber layer disposed between successive piezoelectric crystals and at least one support at a longitudinal end of the transducer configured to cause the crystals to bend.

17. The method of claim 16 wherein the moving fluid through the conduit comprises pumping drilling fluid through an interior of a drill string.

18. The method of claim 16 wherein the moving the conduit comprises longitudinally urging and rotating a drill string, the drill string having a drill bit at a lower end thereof.

19. The method of claim 16 wherein the transducer is configured to have a resonant frequency substantially the same as a frequency of the vibrations induced in the conduit.

20. The method of claim 16 wherein the vibrations result from fluid flow through an interior of the conduit.

21. The method of claim 16 wherein the vibrations result from fluid flow in an annular space between the conduit and a wall of the wellbore.

22. The method of claim 16 further comprising determining a frequency content of the vibrations induced in the conduit, and selecting a resonant frequency of the transducer to substantially match the frequency content.

23. The method of claim 16 further comprising determining a frequency content of the vibrations induced in the conduit, and selecting a resonant frequency of a tuned resonant circuit coupled between an output of the transducer and an electrical load to substantially match the frequency content.