Quantifying cement bonding quality of cased-hole wells using a quality index based on frequency spectra

Patent metadata

Field	Value
Publication number	US-11566517-B2
Application number	US-202117398287-A
Country	US
Kind code	B2
Filing date	Aug 10, 2021
Priority date	Aug 13, 2020
Publication date	Jan 31, 2023
Grant date	Jan 31, 2023

Abstract

A method for characterizing a bond between a first tubular disposed in a borehole and a structure outside of the tubular, the method includes transmitting a signal into and through the first tubular using a signal transmitter conveyed through the borehole and detecting a return signal using a return signal receiver conveyed through the borehole to provide return signal information in a time domain. The method also includes transforming the return signal information in the time domain to return signal information in a frequency domain using a transform and determining a difference between the return signal information in the frequency domain and reference frequency domain return signal information. The method further includes characterizing the bond of the first tubular to the structure outside of the first tubular using the difference to provide a characterization of the bond.

First claim

What is claimed:

1. A method for characterizing a bond between a first tubular disposed in a borehole and a structure outside of the first tubular, the method comprising:
transmitting a signal into and through the first tubular using a signal transmitter conveyed through the borehole;
detecting a return signal using a return signal receiver conveyed through the borehole to provide return signal information in a time domain;
transforming the return signal information in the time domain to return signal information in a frequency domain using a transform;
determining at least one of (i) a Quality Index (QI) value based upon an average of a ratio of an amplitude spectrum of the return signal information in the frequency domain for a first selected frequency range to a reference amplitude spectrum for a reference structure for the first selected frequency range or (ii) a cross-correlation coefficient that quantifies a difference between the amplitude spectrum of the return signal information for a selected second frequency range and the reference amplitude spectrum for the reference structure for the selected second frequency range; and
characterizing the bond of the first tubular to the structure outside of the first tubular using the at least one of the QI value or the cross-correlation coefficient.

2. The method according to claim 1 , wherein the structure comprises a borehole wall.

3. The method according to claim 1 , wherein the structure comprises a second tubular.

4. The method according to claim 3 , wherein the first tubular is bonded to the second tubular using a first bond and the second tubular is bonded to a borehole wall.

5. The method according to claim 1 , wherein the bond comprises cement.

6. The method according to claim 1 , wherein the transmitted signal comprises acoustic waves.

7. The method according to claim 1 , wherein the transmitted signal comprises electromagnetic waves.

8. The method according to claim 1 , wherein the transmitted signal comprises radiation.

9. The method according to claim 8 , wherein the radiation comprises a neutron pulse.

10. The method according to claim 8 , wherein the return signal comprises at least one of gamma radiation and neutron radiation.

11. The method according to claim 1 , wherein the transform comprises at least one of a Fourier transform, a Fast Fourier transform, a Short-Time Fourier transform, a sine wave transform, or a cosine wave transform.

12. The method according to claim 1 , further comprising performing a borehole-related action in response to the characterization of the bond.

13. The method according to claim 1 , further comprising detecting a defect in the bond by comparing the QI value to a threshold value.

14. The method according to claim 1 , wherein transmitting a signal comprises transmitting a plurality of signals using a plurality of signal transmitters.

15. The method according to claim 14 , wherein detecting a return signal comprises detecting a plurality of return signals using a plurality of return signal receivers.

16. The method according to claim 1 , wherein characterizing the bond comprises identifying a defect in the bond and a location of the defect.

17. The method according to claim 1 , wherein the Quality Index value represented as QI m is determined as follows:

Q
⁢

I

m

=

[

1

N
Z

⁢

∑

k
=
0

N
Z

-
1

R
m

(
k
)

]

-
1

,

m
=

m
s

,

m
s

+
1

,
…

,

m
e

N
Z

=

ceiling
(

Z

f
s

⁢
N

)

where:
m: sequential number of the m-th depth point in the vertical interval of data processing;
m s : sequential number of the first depth point in the vertical interval of data processing;
m e : sequential number of the last depth point in the vertical interval of data processing;
R m (k): R m (k)=A m (k)/A ref (k) is the frequency amplitude spectrum ratio for the k-th frequency;
A m : frequency amplitude spectrum at m-th depth point;
A ref frequency amplitude spectrum for reference structure condition;
N: length of frequency spectrum;
N Z : sequential number of frequency point at highest frequency Z of a frequency range;
ceiling: is math operator for rounding a number up to the nearest integer; and
f s : sampling frequency of signal.

18. The method according to claim 17 , wherein Z=40 kHz, the first frequency range is 0 to 40 kHz, and the reference structure condition is that of a free pipe.

19. An apparatus for characterizing a bond of a first tubular disposed in a borehole to a structure outside of the first tubular, the apparatus comprising:
a carrier configured to be conveyed through the borehole;
a signal transmitter disposed on the carrier and configured to transmit a signal into and through the first tubular;
a return signal detector disposed on the carrier and configured to detect a return signal to provide return signal information in a time domain; and
a processor configured to: (i) transform the return signal information in the time domain to return signal information in a frequency domain using a transform; (ii) deter

Assignees

• Li Baoyan
• Yogeswaren Elan
• Ramirez Marc
• Baker Hughes Oilfield Operations Llc

Inventors

• Li Baoyan
• Yogeswaren Elan
• Ramirez Marc

Classifications

• E21B43/10

  Setting of casings, screens, liners {or the like} in wells · CPC title

• E21B47/16 Primary

  through the drill string or casing {, e.g. by torsional acoustic waves} · CPC title

• E21B47/005 Primary

  Monitoring or checking of cementation quality or level · CPC title