Determining a quantitative bond using signal attenuation

Patent metadata

Field	Value
Publication number	US-10539698-B2
Application number	US-201514735079-A
Country	US
Kind code	B2
Filing date	Jun 9, 2015
Priority date	Jun 18, 2014
Publication date	Jan 21, 2020
Grant date	Jan 21, 2020

Abstract

A technique facilitates determination of a quantitative bond between a pipe and adjacent materials, e.g. between a wellbore casing and adjacent cement. The quantitative bond is established via acoustic measurements related to signal attenuation. Additionally, the acoustic measurements may be conducted with a sonic tool during a wellbore operation, e.g. during a drilling operation. The methodology enables use of signal attenuation in a manner which facilitates determination of bond index coverage up to a high percentage, e.g. 100 percent.

First claim

What is claimed is:

1. A method of evaluating bonding of cement in a wellbore, comprising:
providing, as a drill collar that is part of a drill string, a bond analysis tool with a transmitter and a plurality of receivers;
delivering the bond analysis tool downhole along an interior of a pipe having pipe sections;
emitting sonic signals via the transmitter for propagation along the pipe until received by the plurality of receivers;
processing an amplitude of a received combination of propagating sonic signals inside the drill collar and inside the pipe, wherein the propagating sonic signals comprise a combination of a propagating drill collar signal and a propagating pipe signal;
computing an apparent attenuation of the propagating sonic signals, wherein a range of apparent attenuations increases with amount of transmitter signal energy imparted to the drill collar as the propagating drill collar signal; and
using the apparent attenuation between various pairs of receivers of the plurality of receivers as being dependent on a ratio of the propagating drill collar signal to the propagating pipe signal and attenuation in a receiver section of the drill collar to extract the attenuation in the pipe for evaluation of bonding between the pipe and a surrounding cement.

2. The method as recited in claim 1 , wherein computing comprises extracting a parameter related to the amplitude of the sonic signals via a spectral method.

3. The method as recited in claim 1 , wherein computing comprises extracting a parameter related to the amplitude of the sonic signals via a Fourier transformation.

4. The method as recited in claim 1 , wherein computing comprises extracting a parameter related to the amplitude of the sonic signals via a wavelet transformation.

5. The method as recited in claim 1 , further comprising providing a quantitative bond index up to 100% between the pipe and the cement along a desired length of the pipe.

6. The method as recited in claim 1 , wherein providing comprises providing the bond analysis tool in the form of a logging-while-drilling tool.

7. The method as recited in claim 1 , wherein delivering comprises delivering the bond analysis tool along an interior of well casing.

8. The method as recited in claim 1 , further comprising forming the plurality of receivers into an array of at least 10 receivers.

9. A method, comprising:
providing, as a drill collar that is part of a drill string, a bond analysis tool with a transmitter and a plurality of receivers;
delivering the bond analysis tool into a pipe and emitting a signal via the transmitter;
processing an amplitude of a combination of propagating signals resulting from the signal emitted by the transmitter and received by the plurality of receivers;
computing an apparent attenuation of the propagating signals, wherein the propagating signals comprise a combination of a propagating drill collar signal and a propagating pipe signal and wherein a range of apparent attenuations increases with amount of transmitter signal energy imparted to the drill collar as the propagating drill collar signal;
employing the apparent attenuation between various pairs of receivers of the plurality of receivers, as being dependent on a ratio of the propagating drill collar signal to the propagating pipe signal and attenuation in a receiver section of the drill collar, to extract the attenuation in the pipe; and
using the attenuation in the pipe to determine whether sections of the pipe are free or constrained.

10. The method as recited in claim 9 , wherein providing comprises providing the bond analysis tool in the form of a logging-while-drilling tool.

11. The method as recited in claim 10 , wherein positioning the bond analysis tool comprises positioning the bond analysis tool in a casing located in a borehole.

12. The method as recited in claim 10 , wherein positioning the bond analysis tool comprises conveying the bond analysis tool downhole with the drill string during a drilling operation and locating the bond analysis tool in the pipe wherein the pipe is a casing positioned in a borehole and surrounded by cement.

13. The method as recited in claim 12 , wherein using comprises determining a quantitative bond index between the casing and the cement.

14. The method as recited in claim 9 , wherein employing comprises extracting a parameter related to the amplitude of the sonic signals via a spectral method.

15. The method as recited in claim 12 , further comprising forming the plurality of receivers into an array of at least 10 receivers.

16. The method as recited in claim 15 , further comprising coupling the bond analysis tool with a control system positioned at a surface location.

17. A system, comprising:
a wellbore lined with a casing and cement located along an exterior of the casing;
a logging-while-drilling tool that is in the form of a drill collar that is deployable as part of a drill string into the casing via a conveyance, the logging-while-drilling tool having a transmitter to provide a sonic signal and a plurality of receivers position to receive combinations of propagating signals resulting from the sonic signal; and
a processor-based control system coupled with the logging-while-drilling tool to process amplitudes of the combinations of propagating signals, to compute an apparent attenuation of the propagating signals, and to determine the apparent attenuation between various pairs of receivers of the plurality of receivers to extract the attenuation in the casing, as being dependent on a ratio of a propagating drill collar signal to a propagating casing signal and attenuation in a receiver section of the drill collar, for evaluation of bonding between the casing and the cement, wherein a range of apparent attenuations increases with amount of transmitter sonic signal energy imparted to the drill collar as the propagating drill collar signal.

18. The device system as recited in claim 17 , wherein the plurality of receivers comprises an array of at least 12 receivers.

Assignees

• Schlumberger Technology Corp

Inventors

• Pistre Vivian
• Kinoshita Toshihiro

Classifications

• G01V1/50 Primary

  Analysing data · CPC title

• E21B47/0005

  Fixed Constructions · mapped topic

• E21B47/005 Primary

  Monitoring or checking of cementation quality or level · CPC title