Bender bar transducer with at least three resonance modes
AssigneeHalliburton Energy Services, Inc.
InventorsJing Jin, Chung Chang
Life of this patent
Estimating the term…
Abstract
A bender bar acoustic transducer capable of exciting at least three resonance modes is provided. The provided bender bar acoustic transducer may be capable of exciting a second resonance mode by configuring a first portion of a piezoelectric element to contract while a second portion of the piezoelectric element expands when voltage is applied to electrodes coupled to the piezoelectric element. The bender bar acoustic transducer may be further configured such that the first portion and the second portion of the piezoelectric element both contract and/or expand to excite a first resonance mode. The bender bar acoustic transducer may be used in downhole and well logging applications.
Claims25
An acoustic transducer, comprising:
- a substrate element;
- a first piezoelectric element coupled to a first side of the substrate element, the first piezoelectric element comprising a first portion having a set of electrodes and a second portion having a set of electrodes;
- a second piezoelectric element coupled to a second side of the substrate element, the second piezoelectric element comprising a first portion having a set of electrodes and a second portion having a set of electrodes;
- and
- a voltage source coupled to the first and second piezoelectric element to provide:
- application of a first alternating voltage to the acoustic transducer to thereby drive the acoustic transducer to vibrate at a first and third resonance mode that are symmetric with respect to a central plane that passes through the first and second piezoelectric elements;
- and
- application of a second anti-phase voltage to the acoustic transducer to thereby drive the acoustic transducer to vibrate at a second resonance mode having a frequency between the first and third resonance modes and that is asymmetric with respect to the central plane, the second anti-phase voltage having an anti-phase component of the first alternating voltage.
A method utilizing an acoustic logging tool within a borehole, the method comprising:
- deploying the acoustic logging tool into the borehole;
- application of a first alternating voltage to the acoustic logging tool to thereby drive the acoustic logging tool to vibrate at a first and third resonance mode that are symmetric with respect to a central plane that passes through an acoustic transducer of the acoustic logging tool;
- application of a second anti-phase voltage to the acoustic logging tool to thereby drive the acoustic logging tool to vibrate at a second resonance mode having a frequency between the first and third resonance modes and that is asymmetric with respect to the central plane;
- using at least the first, second, or third resonance modes of the acoustic logging tool to produce an acoustic force along the borehole;
- and
- processing a received acoustic response to the produced acoustic force to determine properties of formations surrounding the borehole.
A method of utilizing an acoustic transducer comprising:
- applying a first alternating voltage to a first portion of a first piezoelectric element of the acoustic transducer to cause a first stress on the first portion of the first piezoelectric element;
- applying a second anti-phase voltage to a second portion of a first piezoelectric element to cause a second stress on the second portion of the first piezoelectric element, the second anti-phase voltage having an anti-phase component of the first alternating voltage;
- applying the first alternating voltage to a first portion of a second piezoelectric element to cause the second stress on the first portion of the second piezoelectric element;
- and
- applying the second anti-phase voltage to a second portion of a second piezoelectric element to cause the first stress on the second portion of the second piezoelectric element,
- wherein the acoustic transducer is driven to vibrate at a first and third resonance mode that are symmetric with respect to a central plane that passes through the acoustic transducer and at a second resonance mode that is asymmetric with respect to the central plane.
A method of utilizing an acoustic transducer comprising:
- bending a surface of a piezoelectric transducer in a first direction by applying a first alternating voltage to a first piezoelectric element disposed on said surface and by applying a second anti-phase voltage to a second piezoelectric element disposed on said surface,
- wherein the acoustic transducer is driven to vibrate at a first and third resonance mode that are symmetric with respect to a central plane that passes through the acoustic transducer and at a second resonance mode that is asymmetric with respect to the central plane, the second resonance mode having a frequency between the first and third resonance modes.
Dependencies are inferred from the claim text.