Through tubing cement evaluation based on casing extensional waves

Patent metadata

Field	Value
Publication number	US-2023194743-A1
Application number	US-202117645193-A
Country	US
Kind code	A1
Filing date	Dec 20, 2021
Priority date	Dec 20, 2021
Publication date	Jun 22, 2023
Grant date	—

Abstract

A method comprises conveying a downhole tool in a production tubing within a casing that is around a wall of a wellbore formed in a subsurface formation, wherein cement is placed in an annulus defined between the casing and the wall of the wellbore. The downhole tool includes at least one unipole receiver and a transmitter that comprises at least one of a unipole transmitter and a monopole transmitter. The transmitter and receiver are mounted on a rotatable portion of the downhole tool. The method includes performing the following operations at at least two azimuthal positions, emitting an acoustic transmission outward toward the cement and detecting an acoustic response that is in response to the acoustic transmission propagating through the production tubing and the casing and into the cement. The acoustic response includes casing extensional waves, casing non-extensional waves, and tubing waves. The method includes evaluating the cement based on the casing extensional waves.

First claim

What is claimed is:

1 . A method comprising:
conveying a downhole tool in a production tubing within a casing that is around a wall of a wellbore formed in a subsurface formation, wherein cement is placed in an annulus defined between the casing and the wall of the wellbore, wherein the downhole tool includes a transmitter that comprises at least one of a unipole transmitter and a monopole transmitter, and wherein the downhole tool comprises at least one unipole receiver, wherein the transmitter and the at least one unipole receiver are mounted on a rotatable portion of the downhole tool; performing the following operations at at least two azimuthal positions based on rotation of the rotatable portion,
emitting, from the transmitter, an acoustic transmission outward toward the cement;
detecting, by the at least one unipole receiver, an acoustic response that is in response to the acoustic transmission propagating through the production tubing and the casing and into the cement, the acoustic response including waves that comprise casing extensional waves, casing non-extensional waves, and tubing waves; and
evaluating the cement based on the casing extensional waves.

2 . The method of claim 1 , further comprising:
processing the acoustic response, wherein the processing comprises,
applying a filter to the waves of the acoustic response to remove azimuthal waveforms from the acoustic response to output a filtered acoustic response having the casing extensional waves and casing non-extensional waves but a reduced number of the tubing waves, and
wherein evaluating the cement comprises evaluating the cement based on the filtered acoustic response.

3 . The method of claim 2 , wherein the processing of the acoustic response comprises:
applying a time window to the filtered acoustic response to retain the waves in the filtered acoustic response having a propagation velocity that is greater than a propagation threshold to output a filtered windowed acoustic response that includes the casing extensional waves and a reduced number of the casing non-extensional waves, wherein evaluating the cement comprises evaluating the cement based on the filtered windowed acoustic response.

4 . The method of claim 3 , wherein processing the acoustic response comprises:
determining at least one of an amplitude and an attenuation of the casing extensional waves in the filtered windowed acoustic response, wherein evaluating the cement comprises evaluating the cement based on the at least one of the amplitude and the attenuation of the casing extensional waves in the filtered windowed acoustic response.

5 . The method of claim 4 , further comprising:
determining an eccentricity of the production tubing that defines an offset of a position of the production tubing from the center of the wellbore, wherein processing of the acoustic response comprises adjusting the least one of the amplitude and the attenuation of the casing extensional waves based on the eccentricity of the production tubing, wherein evaluating the cement comprises evaluating the cement based on the at least one adjusted amplitude and the adjusted attenuation of the casing extensional waves.

6 . The method of claim 3 , further comprising:
generating a multi-dimensional bonding index map based on the filtered windowed acoustic response, wherein evaluating the cement comprises evaluating the cement based on the multi-dimensional bonding index map.

7 . The method of claim 1 , wherein evaluating the cement comprises evaluating a cement bonding of the cement.

8 . The method of claim 1 , further comprising:
performing a downhole operation based on the evaluating of the cement.

9 . A system comprising:
a downhole tool configured to be conveyed in a production tubing within a casing that is around a wall of a wellbore formed in a subsurface formation, wherein cement is placed in an annulus defined between the casing and the wall of the wellbore, wherein the downhole tool comprises,
an acoustic transmitter positioned on a rotatable portion of the downhole tool, wherein the acoustic transmitter comprises at least one of a unipole transmitter and a monopole transmitter, wherein the acoustic unipole transmitter is to emit an acoustic transmission outward toward the cement at at least two azimuthal positions based on rotation of the rotatable portion; and
an acoustic unipole receiver to detect an acoustic response that is in response to the acoustic transmission propagating through the production tubing and the casing and into the cement, the acoustic response including waves that comprise casing extensional waves, casing non-extensional waves, and tubing waves;
a processor; and a machine-readable medium having program code executable by the processor to cause the processor to,
evaluate the cement based on the casing extensional waves.

10 . The system of claim 9 , wherein the program code executable by the processor to cause the processor to process the acoustic response comprises program code executable by the processor to cause the processor to,
apply a filter to the waves of the acoustic response to remove azimuthal waveforms from the acoustic response to output a filtered acoustic response having the casing extensional waves and casing non-extensional waves but a reduced number of the tubing waves, and wherein the program code executable by the processor to cause the processor to evaluate the cement comprises program code executable by the processor to cause the processor to evaluate the cement based on the filtered acoustic response.

11 . The system of claim 10 , wherein the program code executable by the processor to cause the processor to process the acoustic response comprises program code executable by the processor to cause the processor to,
apply a time window to the filtered acoustic response to retain the waves in the filtered acoustic response having a propagation velocity that is greater than a propagation threshold to output a filtered windowed acoustic response that includes the casing extensional waves and a reduced number of the casing non-extensional waves, wherein the program code executable by the processor to cause the processor to evaluate the cement comprises program code executable by the processor to cause the processor to evaluate the cement based on the filtered windowed acoustic response.

12 . The system of claim 11 , wherein the program code executable by the processor to cause the processor to process the acoustic response comprises program code executable by the processor to cause the processor to,
determine at least one of an amplitude and an attenuation of the casing extensional waves in the filtered windowed acoustic response, wherein the program code executable by the processor to cause the processor to evaluate the cement comprises program code executable by the processor to cause the processor to evaluate the cement based on the at least one of the amplitude and the attenuation of the casing extensional waves in the filtered windowed acoustic response.

13 . The system of claim 12 , wherein the program code comprises program code executable by the processor to cause the processor to,
determine an eccentricity of the production tubing that defines an offset of a position of the production tubing from the center of the wellbore, wherein the program code executable by the processor to cause the processor to process the acoustic response comprises program code executable by the processor to cause the processor to adjust the least one of the amplitude and the attenuation of the casing extensional waves based on the eccentricity of

Assignees

• Halliburton Energy Services Inc

Inventors

• Wang Ruijia
• Ge Yao
• Cabella Brenno Caetano Troca
• Chang Chung
• Jin Jing
• Ma Ho Yin
• Wu Xiang

Classifications

• G01V2210/1429

  Subsurface, e.g. in borehole or below weathering layer or mud line · CPC title

• G01V2210/60

  Analysis · CPC title

• G01V2210/1299

  Subsurface, e.g. in borehole or below weathering layer or mud line · CPC title

• E21B47/005 Primary

  Monitoring or checking of cementation quality or level · CPC title

• G01B17/06

  for measuring contours or curvatures · CPC title