Casing thickness measurement using acoustic wave correlation

Patent metadata

Field	Value
Publication number	US-10712466-B2
Application number	US-201414413404-A
Country	US
Kind code	B2
Filing date	Jul 15, 2014
Priority date	Aug 15, 2013
Publication date	Jul 14, 2020
Grant date	Jul 14, 2020

Abstract

Systems, methods, and software for determining a thickness of a well casing are described. In some aspects, the thickness of the well casing is determined based on results of comparing a measured waveform and model waveforms. The measured waveform and model waveforms are generated based on operating an acoustic transmitter and an acoustic receiver within a wellbore comprising the well casing.

First claim

What is claimed is:

1. A method comprising:
disposing a tool in a wellbore;
directing an acoustic signal towards a well casing in the wellbore, the acoustic signal generated by an acoustic transmitter of the tool;
accessing a measured waveform associated with an acoustic signal returned via the well casing based on operating an acoustic receiver of the tool within the wellbore comprising the well casing;
comparing the measured waveform to a plurality of model waveforms, wherein each of the plurality of model waveforms corresponds to a different thickness of the well casing;
determining, by operation of data processing apparatus, a thickness of the well casing based on results of comparing the measured waveform and the plurality of model waveforms; and
assessing damage to the well casing based on the determined thickness of the well casing.

2. The method of claim 1 , wherein comparing the measured waveform to the plurality of model waveforms comprises determining correlations between at least a portion of the measured waveform and at least a portion of each of the plurality of model waveforms.

3. The method of claim 2 , wherein the at least a portion of the measured waveform corresponds to a reverberation window of the measured waveform.

4. The method of claim 2 , wherein determining the correlations between the at least a portion of the measured waveform and the at least a portion of each of the plurality of model waveforms comprises determining cross-correlations between the at least a portion of the measured waveform and the at least a portion of each of the plurality of model waveforms.

5. The method of claim 2 , wherein:
determining the correlations between the at least a portion of the measured waveform and the at least a portion of each of the plurality of model waveforms comprises determining differences between the at least a portion of the measured waveform and the at least a portion of each of the plurality of model waveforms; and
determining the thickness of the well casing comprises determining a thickness corresponding to a model waveform of the plurality of model waveforms corresponding to a minimum difference of the determined differences.

6. The method of claim 1 , further comprising:
generating the plurality of model waveforms for a plurality of assumed thicknesses based on one or more of (i) a reflection of the acoustic signal, (ii) a radiation pattern of the acoustic transmitter, and (iii) a curvature of the well casing.

7. The method of claim 1 , wherein determining the thickness of the well casing comprises determining the thickness of the well casing in real time during drilling operations or wireline logging operations.

8. A non-transitory computer-readable medium encoded with instructions that, when executed by data processing apparatus, cause the data processing apparatus to perform operations comprising:
accessing a measured waveform associated with an acoustic signal returned via a well casing based on operating an acoustic transmitter and an acoustic receiver of a tool disposed within a wellbore comprising the well casing, the acoustic transmitter generating an acoustic signal directed towards the well casing;
comparing the measured waveform to a plurality of model waveforms, wherein each of the plurality of model waveforms corresponds to a different thickness of the well casing;
determining a thickness of the well casing based on results of comparing the measured waveform and the plurality of model waveforms; and
assessing damage to the well casing based on the determined thickness of the well casing.

9. The non-transitory computer-readable medium of claim 8 , wherein comparing the measured waveform to the plurality of model waveforms comprises determining correlations between at least a portion of the measured waveform and at least a portion of each of the plurality of model waveforms.

10. The non-transitory computer-readable medium of claim 9 , wherein the at least a portion of the measured waveform corresponds to a reverberation window of the measured waveform.

11. The non-transitory computer-readable medium of claim 9 , wherein determining the correlations between the at least a portion of the measured waveform and the at least a portion of each of the plurality of model waveforms comprises determining cross-correlations between the at least a portion of the measured waveform and the at least a portion of each of the plurality of model waveforms.

12. The non-transitory computer-readable medium of claim 9 , wherein:
determining the correlations between the at least a portion of the measured waveform and the at least a portion of each of the plurality of model waveforms comprises determining differences between the at least a portion of the measured waveform and the at least a portion of each of the plurality of model waveforms; and
determining the thickness of the well casing comprises determining a thickness corresponding to a model waveform of the plurality of model waveforms corresponding to a minimum difference of the determined differences.

13. The non-transitory computer-readable medium of claim 8 , further comprising generating the plurality of model waveforms for a plurality of assumed thicknesses based on one or more of (i) a reflection of the acoustic signal, (ii) a radiation pattern of the acoustic transmitter, and (iii) a curvature of the well casing.

14. The non-transitory computer-readable medium of claim 8 , wherein determining the thickness of the well casing comprises determining the thickness of the well casing in real time during drilling operations or wireline logging operations.

15. A system comprising:
an acoustic transmitter-receiver pair of a tool to be disposed within a wellbore comprising a well casing, the acoustic transmitter generating an acoustic signal and transmitting the acoustic signal towards the well casing; and
a computing system coupled with the acoustic transmitter-receiver pair, the computing system is configured to:
access a measured waveform associated with an acoustic signal returned via the well casing based on operating the acoustic receiver of the tool within an interior portion of the well casing;
compare the measured waveform to a plurality of model waveforms, wherein each of the plurality of model waveforms corresponds to a different thickness of the well casing;
determine a thickness of the well casing based on results of comparing the measured waveform and the plurality of model waveforms; and
assessing damage to the well casing based on the determined thickness of the well casing.

16. The system of claim 15 , wherein the computing system is configured to:
compare the measured waveform to the plurality of model waveforms; and
determine correlations between at least a portion of the measured waveform and at least a portion of each of the plurality of model waveforms.

17. The system of claim 16 , wherein the at least a portion of the measured waveform corresponds to a reverberation window of the measured waveform.

18. The system of claim 16 , wherein the computing system is configured to:
determine the correlations between the at least a portion of the measured waveform and the at least a portion of each of the plurality of model waveforms; and
determine cross-correlations between the at least a portion of the measured waveform and the at least a portion of each of the plurality of model waveforms.

19. The system of claim 16 , wherein the computing system is configured to:
determine the correlations between the at least a porti

Assignees

• Halliburton Energy Services Inc

Inventors

• Chen Tianrun
• Zheng Yibing
• Gilstrap Tatiana
• Cheng Arthur Chuen Hon
• Epstein Robert Eric

Classifications

• E21B47/006

  Detection of corrosion or deposition of substances · CPC title

• G01V2210/542

  Casing · CPC title

• E21B47/085

  using radiant means, e.g. acoustic, radioactive or electromagnetic · CPC title

• G01V1/44

  using generators and receivers in the same well (G01V1/52 takes precedence) · CPC title

• G01V1/48 Primary

  Processing data · CPC title