Ultrasonic transducer with reduced backing reflection

Patent metadata

Field	Value
Publication number	US-11480702-B2
Application number	US-201816463689-A
Country	US
Kind code	B2
Filing date	Jun 27, 2018
Priority date	Jun 27, 2018
Publication date	Oct 25, 2022
Grant date	Oct 25, 2022

Abstract

A well tool can be used in a wellbore that can measure characteristics of an object in the wellbore. The well tool includes an ultrasonic transducer for generating an ultrasonic wave in a medium of the wellbore. The ultrasonic transducer includes a front layer, a rear layer, backing material coupled to the rear layer, and piezoelectric material coupled to the front layer and to the backing material. The rear layer can improve signal-to-noise ratio of the transducer in applications such as imaging and caliper applications.

First claim

What is claimed is:

1. A well tool usable in a wellbore, the well tool comprising:
an ultrasonic transducer for generating an ultrasonic wave in an acoustic medium of the wellbore, the ultrasonic transducer comprising:
a front layer;
a piezoelectric layer comprising a first side and a second side, the front layer coupled to the first side of the piezoelectric layer;
a backing layer comprising a first side and a second side, the second side of the piezoelectric layer coupled to the first side of the backing layer; and
a rear layer comprising:
a first side coupled to the second side of the backing layer;
a second side of the rear layer positionable to abut the acoustic medium; and
a thickness between the first side and the second side that is one-fourth of a wavelength of a velocity of sound in a material of the rear layer.

2. The well tool of claim 1 , wherein the front layer is a front quarter-wavelength plate.

3. The well tool of claim 1 , wherein the ultrasonic transducer is an ultrasound ultrasonic transducer for outputting the ultrasonic wave at a frequency of 20 kHz or higher.

4. The well tool of claim 1 , wherein the well tool comprises a logging-while-drilling tool or a wireline tool.

5. The well tool of claim 1 , further comprising:
an ultrasonic sensor for detecting a reflection or a refraction of the ultrasonic wave off an object in the wellbore and transmitting an associated signal;
a processing device in communication with the ultrasonic transducer and the ultrasonic sensor; and
a memory device in which instructions are stored that are executable by the processing device for causing the processing device to:
receive the associated signal from the ultrasonic sensor; and
determine a characteristic of the object based on the associated signal.

6. The well tool of claim 5 , wherein the characteristic is an image of the object.

7. The well tool of claim 5 , wherein the characteristic is a measured diameter of part of the wellbore determined by a caliper application, an impedance of borehole material, or an existence of a deformity of a wall of the wellbore.

8. A sensor system for use in a wellbore, the sensor system comprising:
an ultrasonic transducer for generating an ultrasonic wave in an acoustic medium of the wellbore, the ultrasonic transducer comprising:
a front layer;
a piezoelectric layer comprising a first side and a second side, the front layer coupled to the first side of the piezoelectric layer;
a backing layer comprising a first side and a second side, the second side of the piezoelectric layer coupled to the first side of the backing layer; and
a rear layer comprising:
a first side coupled to the second side of the backing layer;
a second side of the rear layer positionable to abut the acoustic medium; and
a thickness between the first side and the second side that is one-fourth of a wavelength of a velocity of sound in a material of the rear layer; and

a hydrophone for detecting a reflection or a refraction of the ultrasonic wave off an object in the wellbore and transmitting an associated signal to a processing device.

9. The sensor system of claim 8 , wherein the ultrasonic transducer is an ultrasound ultrasonic transducer for outputting the ultrasonic wave at a frequency of 20 kHz or higher.

10. The sensor system of claim 8 , wherein the sensor system is in a logging-while-drilling tool or a wireline tool.

11. The sensor system of claim 8 , further comprising:
the processing device in communication with the ultrasonic transducer and the hydrophone; and
a memory device in which instructions are stored that are executable by the processing device for causing the processing device to:
receive the associated signal from the hydrophone; and
determine a characteristic of the object based on the associated signal.

12. The sensor system of claim 11 , wherein the characteristic is an image of the object.

13. The sensor system of claim 11 , wherein the characteristic is a measured diameter of part of the wellbore determined by a caliper application, an impedance of borehole material, or an existence of a deformity of a wall of the wellbore.

14. A method, comprising;
disposing a well tool in a wellbore, the well tool including a hydrophone and an ultrasonic transducer, the ultrasonic transducer comprising:
a front layer;
a piezoelectric layer comprising a first side and a second side, the front layer coupled to the first side of the piezoelectric layer;
a backing layer comprising a first side and a second side, the second side of the piezoelectric layer coupled to the first side of the backing layer; and
a rear layer comprising:
a first side coupled to the second side of the backing layer;
a second side of the rear layer positioned to abut an ultrasonic medium of the wellbore; and
a thickness between the first side and the second side that is one-fourth of a wavelength of a velocity of sound in a material of the rear layer;

outputting, by the ultrasonic transducer, an ultrasonic wave in the ultrasonic medium of the wellbore;
detecting, by the hydrophone, a reflection or a refraction of the ultrasonic wave off an object in the wellbore;
generating, by the hydrophone, a representative signal of the reflection or the refraction of the ultrasonic wave off the object in the wellbore; and
using the representative signal to determine a characteristic of the object.

15. The method of claim 14 , wherein the front layer is a front quarter-wavelength plate,
wherein the ultrasonic transducer is an ultrasound ultrasonic transducer for outputting the ultrasonic wave at a frequency of 20 kHz or higher.

16. The method of claim 14 , wherein the well tool is a logging-while-drilling tool or a wireline tool.

17. The method of claim 14 , wherein the characteristic is an image of the object.

18. The method of claim 14 , wherein the characteristic is a measured diameter of part of the wellbore determined by a caliper application, an impedance of borehole material, or an existence of a deformity of a wall of the wellbore.

Assignees

• Halliburton Energy Services Inc

Inventors

• Jin Jing
• Ge Yao
• Li Wei
• Wu Xiang

Classifications

• G01V1/159

  using piezoelectric or magnetostrictive driving means (generating mechanical vibrations by using piezoelectric or magnetostrictive effect in general, B06B1/06, B06B1/08) · CPC title

• G01V1/52

  Structural details · CPC title

• E21B47/022

  of the borehole, e.g. using geomagnetism · CPC title

• G01V1/50 Primary

  Analysing data · CPC title

• B06B1/0644

  using a single piezoelectric element (B06B1/0688 takes precedence) · CPC title