Hybrid piezoelectric and magnetostrictive actuator

• US 6,998,999 B2
• Filed: 04/08/2003
• Issued: 02/14/2006
• Est. Priority Date: 04/08/2003
• Status: Expired due to Fees

• Current Assignee: Halliburton Energy Services Incorporated (Halliburton Company)
• Original Assignee: Halliburton Energy Services Incorporated (Halliburton Company)
• Inventors: Schultz, Roger L., Fripp, Michael L.
• Primary Examiner(s): WONG, ALBERT KANG
• Application Number:
  US10/409,558
• Publication Number:
  US 20040202047A1
• Time in Patent Office: 1,043 Days
• Field of Search: 340/854.4, 340/854.3, 367/82, 310/334, 735/70, 166/250.01
• US Class Current: 340/854.4
• CPC Class Codes: B06B 1/06 operating with piezoelectric effect or with electrostriction piezoelectric or electrostrictive devices per se H10N30/00
• CPC Class Codes: B06B 1/08 operating with magnetostriction magnetostrictive devices per se H10N30/00
• CPC Class Codes: E21B 47/14 using acoustic waves
• CPC Class Codes: G01V 1/40 specially adapted for well-logging

Abstract

An electromechanical transducer formed by an electrical and mechanical combination of a piezoelectric device and a magnetostrictive device. The two devices are electrically coupled so that their capacitive and inductive reactances approach a balance to provide an essentially resistive combined input at a selected frequency. Efficiency of circuits driving the transducer is improved. The devices are mechanically coupled so that the mechanical outputs add or reinforce each other. Two transducer pairs may be used in a two frequency telemetry system with each pair tuned to one of the frequencies for optimal reactance balancing and transduction efficiency.

Claims

1. An acoustic telemetry transducer comprising:

a capacitive electromechanical transducer having an electrical connection and a mechanical connection responsive to vibration, and

an inductive electromechanical transducer having an electrical connection coupled to the capacitive electromechanical transducer electrical connection and having a mechanical connection coupled to the capacitive electromechanical transducer mechanical connection.

2. A transducer according to claim 1, wherein the inductive electromechanical transducer electrical connection is coupled in series with the capacitive electromechanical transducer electrical connection.

3. A transducer according to claim 1, wherein:

the inductive electromechanical transducer has an inductance value,

the capacitive electromechanical transducer has a capacitance value, and

the inductance value and the capacitance value are preselected so that the combined impedance of the coupled electrical connections of the inductive electromechanical transducer and the capacitive electromechanical transducer has a reduced reactance over a frequency band near a preselected frequency.

4. A transducer according to claim 3, wherein the mechanical connections of the capacitive electromechanical transducer and the inductive electromechanical transducer have a mechanical resonant frequency different from the preselected frequency, whereby the frequency band of reduced reactance is broadened.

5. A transducer according to claim 3, wherein the combined impedance is essentially resistive at the preselected frequency.

6. A transducer according to claim 1, wherein the capacitive electromechanical transducer comprises a piezoelectric material.

7. A transducer according to claim 6, wherein the piezoelectric material comprises a piezoceramic material.

8. A transducer according to claim 1, wherein the inductive electromechanical transducer comprises a magnetostrictive material.

9. An electromechanical transducer for use in a borehole comprising:

a capacitive electromechanical transducer having an electrical connection and a mechanical connection responsive to displacement or strain, and

an inductive electromechanical transducer having an electrical connection coupled to the capacitive electromechanical transducer electrical connection and having a mechanical connection coupled to the capacitive electromechanical transducer mechanical connection.

10. A transducer according to claim 9, wherein the inductive electromechanical transducer electrical connection is coupled in series with the capacitive electromechanical transducer electrical connection.

11. A transducer according to claim 9, wherein:

the inductive electromechanical transducer has an inductance value,

the capacitive electromechanical transducer has a capacitance value, and

the inductance value and the capacitance value are preselected so that the combined impedance of the coupled electrical connections of the inductive electromechanical transducer and the capacitive electromechanical transducer has a reduced reactance over a frequency band near a preselected frequency.

12. A transducer according to claim 9, wherein the capacitive electromechanical transducer comprises a piezoelectric material.

13. A transducer according to claim 12, wherein the piezoelectric material comprises a piezoceramic material.

14. A transducer according to claim 9, wherein the inductive electromechanical transducer comprises a magnetostrictive material.

15. A transducer according to claim 9, wherein the capacitive electromechanical transducer comprises a flexible piezoelectric device bonded to the surface of a tubular element adapted for use in a borehole.

16. A transducer according to claim 9, wherein:

the inductive electromechanical transducer comprises a section of a tubular element adapted for use in a borehole, and

a coil surrounding the section of tubular element.

17. A transducer according to claim 16, wherein the section of tubular element comprises a magnetostrictive material.

18. A transducer according to claim 16, further comprising a cylindrical sleeve surrounding said coil having an upper end coupled to the tubular element above the coil and having a lower end coupled to the tubular element below the coil.

19. A transducer according to claim 18, wherein the sleeve is permanently magnetized.

20. A transducer according to claim 18, wherein the sleeve comprises a magnetostrictive material.

21. A borehole telemetry system for transmitting signals from a first location in a borehole to a second location in the borehole, comprising:

an acoustic transmission medium extending from the first location to the second location,

a first capacitive electromechanical transducer having an electrical connection and having a mechanical connection coupled to the acoustic transmission medium, and

a first inductive electromechanical transducer having an electrical connection coupled to the first capacitive electromechanical transducer electrical connection and having a mechanical connection coupled to the acoustic transmission medium near the first capacitive electromechanical transducer.

22. A telemetry system according to claim 21, wherein the first inductive electromechanical transducer and the first capacitive electromechanical transducer are both coupled to the transmission medium at the second location and act in cooperation to receive signals.

23. A telemetry system according to claim 21, wherein the first inductive electromechanical transducer and the first capacitive electromechanical transducer are both coupled to the transmission medium at the first location and act in cooperation to transmit signals.

24. A telemetry system according to claim 23, wherein the first inductive electromechanical transducer electrical connection is coupled in series with the first capacitive electromechanical transducer electrical connection.

25. A telemetry system according to claim 23, wherein the first inductive electromechanical transducer mechanical connection is coupled to the first capacitive electromechanical transducer mechanical connection.

26. A telemetry system according to claim 23, wherein

the mechanical connection of the first inductive electromechanical transducer is out of phase with the mechanical connection of the first capacitive electromechanical transducer, and

the first inductive electromechanical transducer is spaced apart from the first capacitive electromechanical transducer by a distance related to the phase difference between the mechanical connection of the inductive electromechanical transducer and the mechanical connection of the capacitive electromechanical transducer.

27. A telemetry system according to claim 23, wherein the first inductive electromechanical transducer comprises a magnetostrictive material.

28. A telemetry system according to claim 23, wherein the first capacitive electromechanical transducer comprises a piezoelectric material.

29. A telemetry system according to claim 28, wherein the piezoelectric material comprises a piezoceramic material.

30. A telemetry system according to claim 23, further comprising:

a second capacitive electromechanical transducer having an electrical connection and having a mechanical connection coupled to the acoustic transmission medium at the second location, and

a second inductive electromechanical transducer having an electrical connection coupled to the piezoelectric device electrical connection and having a mechanical connection coupled to the acoustic transmission medium at the second location.

31. A telemetry system according to claim 30, further comprising a signal transmitter having an output coupled to the electrical connections of the first capacitive electromechanical transducer and the first inductive electromechanical transducer and thereby transmitting an acoustic signal through the acoustic transmission medium.

32. A telemetry system according to claim 31, wherein the signal transmitter transmits signals at one or more frequencies at which the combined reactance of the first capacitive electromechanical transducer and the first inductive electromechanical transducer is reduced.

33. A telemetry system according to claim 31, further comprising a signal receiver having an input coupled to the electrical connections of the second capacitive electromechanical transducer and the second inductive electromechanical transducer and thereby receiving the acoustic signal from the acoustic transmission medium.

34. A telemetry system according to claim 21, wherein the acoustic transmission medium comprises a drill string.

35. A telemetry system according to claim 21, wherein the acoustic transmission medium comprises production tubing.

36. A telemetry system according to claim 21, wherein the acoustic transmission medium comprises a slick line.

37. A telemetry system according to claim 21, wherein the acoustic transmission medium comprises a wire line.

38. A telemetry system according to claim 21, wherein the acoustic transmission medium comprises fluid in the borehole.

39. A telemetry system according to claim 21, wherein the acoustic transmission medium comprises earth formations surrounding the borehole.

40. A borehole telemetry system for transmitting signals from a first location in a borehole to a second location in the borehole, comprising:

an acoustic transmission medium extending from the first location to the second location, and

two transducer pairs, each pair comprising a first capacitive electromechanical transducer having an electrical connection and having a mechanical connection coupled to the acoustic transmission medium near the first location, and a first inductive electromechanical transducer having an electrical connection coupled to the first capacitive electromechanical transducer electrical connection and having a mechanical connection coupled to the acoustic transmission medium at a location spaced operatively from its corresponding capacitive electromechanical transducer.

41. A telemetry system according to claim 40, wherein

a first of the transducer pairs has a first pair inductive electromechanical transducer mechanical connection coupled to the acoustic transmission medium at a location spaced apart from the location at which the first pair capacitive electromechanical transducer mechanical connection is coupled to the acoustic transmission medium by a distance related to a first frequency and the phase difference between the first pair capacitive electromechanical transducer mechanical connection and the first pair capacitive electromechanical transducer mechanical connection, and

a second of the transducer pairs has a second pair capacitive electromechanical transducer mechanical connection coupled to the acoustic transmission medium at a location spaced apart from the location at which the second pair capacitive electromechanical transducer mechanical connection is coupled to the acoustic transmission medium by a distance related to a second frequency and the phase difference between the second pair inductive electromechanical transducer mechanical connection and the second pair capacitive electromechanical transducer mechanical connection.

42. A telemetry system according to claim 41, further comprising a telemetry transmitter having a first output coupled to the electrical connections of said first pair transducers, the first output selectively providing an electrical signal at the first frequency, and having a second output coupled to the electrical connections of said second pair transducers, the second output selectively providing an electrical signal at the second frequency.

43. A telemetry system according to claim 41, wherein the first pair inductive electromechanical transducer and the second pair inductive electromechanical transducer comprise the same inductive electromechanical transducer.

44. A telemetry system according to claim 41, wherein the first pair capacitive electromechanical transducer and the second pair capacitive electromechanical transducer comprise the same capacitive electromechanical transducer.

45. A telemetry system according to claim 41, wherein each of the capacitive electromechanical transducers comprises a piezoelectric material.

46. A telemetry system according to claim 45, wherein the piezoelectric material comprises a piezoceramic material.

47. A telemetry system according to claim 41, wherein each of the inductive electromechanical transducers comprises a magnetostrictive material.

48. A method for transmitting signals from a first location in a borehole to a second location in a borehole, comprising;

coupling the mechanical connection of a first capacitive electromechanical transducer to an acoustic medium at a first point near said first location,

coupling the mechanical connection of a first inductive electromechanical transducer to the acoustic medium at a second point near said first location, the second point being spaced from the first point by a distance related to a first frequency and the phase difference between acoustic signals produced at the mechanical connections of said first capacitive and inductive transducers,

coupling the electrical connections of the first capacitive and inductive transducers together to form a first circuit,

coupling the mechanical connection of a second capacitive electromechanical transducer to an acoustic medium at a third point said first location,

coupling the mechanical connection of a second inductive electromechanical transducer to the acoustic medium at a fourth point near said first location, the fourth point being spaced from the third point by a distance related to a second frequency and the phase difference between acoustic signals produced at the mechanical connections of said second capacitive and inductive transducers,

coupling the electrical connections of the second capacitive and inductive transducers together to form a second circuit.

49. A method according to claim 48, further comprising:

coupling electrical signals to said first circuit at about said first frequency, and

coupling electrical signals to said second circuit at about said second frequency.