US-12618320-B2 - Systems and methods for cement evaluation through tubing using short-term frequency responses

Abstract

In at least one embodiment, a well inspection method and system enables transmission of an acoustic signal from a well inspection tool into a well structure and reception of return signals from the well structure at an array of receivers on the well inspection tool. The method and system enable performing of Short-Term Fourier Transform (STFT) on the return signals to generate spectrogram data that is used to determine short-term power spectra of the return signals. Time-dependent frequency response and location-dependent waveform propagation patterns are identified from the short-term power spectra. Cement bonding conditions is determined based on pattern matching using the time-dependent frequency response patterns and using the location-dependent waveform propagation patterns.

Inventors

• Baoyan Li
• Elan Yogeswaren
• Marc Ramirez
• Joseph Olaiya

Assignees

• BAKER HUGHES OILFIELD OPERATIONS LLC

Dates

Publication Date

20260505

Application Date

20231110

Claims (20)

1. 1 . A well inspection method, comprising: receiving signals transmitted by a transmitter and reflected from a well structure to a receiver of a well inspection tool; performing, using at least one processor, Short-Term Fourier Transform (STFT) on the signals to generate spectrogram data; determining short-term power spectra from the spectrogram data; identifying time-dependent frequency response patterns and location-dependent waveform propagation patterns of the short-term power spectra; and determining cement bonding conditions of the well structure based on: pattern matching using the time-dependent frequency response patterns; and pattern matching using the location-dependent waveform propagation patterns.
2. 2 . The well inspection method of claim 1 , further comprising: retrieving measurement data from the signals; and enabling the at least one processor to access the measurement data and to access patterns of known cement-bonding conditions to perform the pattern matching using the time-dependent frequency response patterns and using the location-dependent waveform propagation patterns.
3. 3 . The well inspection method of claim 1 , further comprising: performing the Short-Term Fourier Transform (STFT) on individual ones of the signals to generate individual ones of spectrograms that are cumulated to generate the spectrogram data.
4. 4 . The well inspection method of claim 1 , further comprising: determining partial energies of the signals at selected time segments from the spectrogram data, the partial energies to be comprised in the short-term power spectra.
5. 5 . The well inspection method of claim 1 , further comprising: using partial energies of the signals at selected time segments from the spectrogram data to perform the identification of the time-dependent frequency response patterns and location-dependent waveform propagation patterns.
6. 6 . The well inspection method of claim 1 , further comprising: comparing the time-dependent frequency response patterns and the location-dependent waveform propagation patterns with second time-dependent frequency response patterns and second location-dependent waveform propagation patterns from known cement-bonding conditions to enable the determination of the cement bonding conditions.
7. 7 . The well inspection method of claim 1 , wherein the signals are received in an array of receivers that are acoustic sensors.
8. 8 . The well inspection method of claim 1 , further comprising: performing swept frequency acoustic interferometry to cover a frequency range in the signals, wherein the frequency range includes frequencies associated with a tubing component, a casing component, a cement component, a well fluid component, and an air component.
9. 9 . The well inspection method of claim 1 , wherein the signals provide coverage of the well structure in different azimuthal directions.
10. 10 . The well inspection method of claim 1 , further comprising: passing the signals to a modelling system to confirm a frequency range of the signals as suitable to expected frequency ranges for the well inspection.
11. 11 . A system for well inspection, comprising: at least one processor; and memory comprising instructions that when executed by the at least one processor enable the system to: perform Short-Term Fourier Transform (STFT) on received signals transmitted by a transmitter and reflected from a well structure to a receiver of a well inspection tool, the STFT to generate spectrogram data for the signals; determine short-term power spectra from the spectrogram data; identify time-dependent frequency response patterns and location-dependent waveform propagation patterns of the short-term power spectra; and determine cement bonding conditions of the well structure based on: pattern matching using the time-dependent frequency response patterns; and pattern matching using the location-dependent waveform propagation patterns.
12. 12 . The system of claim 11 , wherein the at least one processor and the memory comprising the instructions that when executed by the at least one processor further enable the system to: retrieve measurement data from the signals; and enable the at least one processor to access the measurement data and to access patterns of known cement-bonding conditions to perform the pattern matching using the time-dependent frequency response patterns and using the location-dependent waveform propagation patterns.
13. 13 . The system of claim 11 , wherein the at least one processor and the memory comprising the instructions that when executed by the at least one processor further enable the system to: perform the Short-Term Fourier Transform (STFT) on individual ones of the signals to generate individual ones of spectrograms that are cumulated to generate the spectrogram data.
14. 14 . The system of claim 11 , wherein the at least one processor and the memory comprising the instructions that when executed by the at least one processor further enable the system to: determine partial energies of the signals at selected time segments from the spectrogram data, the partial energies to be comprised in the short-term power spectra.
15. 15 . The system of claim 11 , wherein the at least one processor and the memory comprising the instructions that when executed by the at least one processor further enable the system to: use partial energies of the signals at selected time segments from the spectrogram data to perform the identification of the time-dependent frequency response patterns and location-dependent waveform propagation patterns.
16. 16 . The system of claim 11 , wherein the at least one processor and the memory comprising the instructions that when executed by the at least one processor further enable the system to: compare the time-dependent frequency response patterns and the location-dependent waveform propagation patterns with second time-dependent frequency response patterns and second location-dependent waveform propagation patterns from known cement-bonding conditions to enable the determination of the cement bonding conditions.
17. 17 . The system of claim 11 , wherein the signals are received in an array of receivers that are acoustic sensors.
18. 18 . The system of claim 11 , wherein the at least one processor and the memory comprising the instructions that when executed by the at least one processor further enable the system to: perform swept frequency acoustic interferometry to cover a frequency range in the signals, wherein the frequency range includes frequencies associated with a tubing component, a casing component, a cement component, a well fluid component, and an air component.
19. 19 . The system of claim 11 , wherein the signals provide coverage of the well structure in different azimuthal directions.
20. 20 . The system of claim 11 , wherein the at least one processor and the memory comprising the instructions that when executed by the at least one processor further enable the system to: pass the signals to a modelling system to confirm a frequency range of the signals as suitable to expected frequency ranges for the well inspection.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of U.S. patent application Ser. No. 17/850,443, filed Jun. 27, 2022, titled SYSTEMS AND METHODS FOR CEMENT EVALUATION THROUGH TUBING USING SHORT-TERM FREQUENCY RESPONSES, now U.S. Pat. No. 11,828,158 issued Nov. 28, 2023, which is related to and claims the benefit of priority from U.S. Provisional Application 63/216,976, filed Jun. 30, 2021, and titled SYSTEMS AND METHODS FOR CEMENT EVALUATION THROUGH TUBING USING SHORT-TERM FREQUENCY RESPONSES, the entire disclosures of which are incorporated by reference herein for all intents and purposes. BACKGROUND 1. Technical Field This disclosure relates generally to oilfield equipment and more particularly to systems and methods for evaluating cement-bonding quality through tubing or multiple casings. 2. Description of the Prior Art Evaluation of cement-bonding quality can be a challenging process as it requires interpret of acoustic measurements to evaluate cement-bonding quality in a through-tubing process, such as for plugged and abandoned (P&A) wells. For acoustic logging-related through-tubing, most of energy generated by a transmitter may be confined in the tubing because of high impedance contrast of the tubing and fluid. Variances in received waveforms as a result of cement bonding conditions may not be significant or may not be observable. To address this, frequency responses of receivers can be analyzed to recognize features on a frequency spectra of a received waveforms that may be a result of cement bonding conditions. However, such features can be trivial and difficult to reliably identify. In addition, casing-debonding and cement-debonding may not be differentiable using currently-available techniques. SUMMARY In at least one embodiment, a well inspection method is disclosed. The method includes transmitting an acoustic signal from a well inspection tool into a well structure and receiving return signals from the well structure at an array of receivers on the well inspection tool. The method includes performing Short-Term Fourier Transform (STFT) on the return signals to generate spectrogram data. A further step in the method is to determine short-term power spectra from the spectrogram data. A step to identify time-dependent frequency response patterns and location-dependent waveform propagation patterns of the short-term power spectra is performed in the method. The method also includes determining cement bonding conditions based on pattern matching using the time-dependent frequency response patterns and using the location-dependent waveform propagation patterns. In at least one embodiment, a system for well inspection is also disclosed. The system includes a well inspection tool to transmit an acoustic signal into a well structure, an array of receivers on the well inspection tool to receive return signals from the well structure, and at least one processor and memory comprising instructions that when executed by the at least one processor enable the system to perform specific functions. A function is to perform Short-Term Fourier Transform (STFT) on the return signals to generate spectrogram data. Another function is to determine short-term power spectra from the spectrogram data. A further function is to identify time-dependent frequency response and location-dependent waveform propagation patterns of the short-term power spectra. The specific functions include a function to determine cement bonding conditions based on pattern matching using the time-dependent frequency response patterns and using the location-dependent waveform propagation patterns. BRIEF DESCRIPTION OF DRAWINGS Some of the features and benefits of the present disclosure having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which: FIG. 1 is a partial cross-sectional view of a well inspection system, illustrating a well with a plurality barriers, such as casing, tubing, cement layers, and the like, in accordance with at least one embodiment. FIG. 2 illustrates an acoustic inspection tool for performing well structure inspection, in accordance with at least one embodiment. FIG. 3 illustrates an acoustic inspection tool with azimuthally distributed receivers, in accordance with at least one embodiment. FIG. 4 is a flowchart illustrating a well structure inspection and analysis technique, in accordance with at least one embodiment. FIG. 5 is a block diagram of computer and network aspects for a well inspection system as described in FIGS. 1-4 herein, in accordance with at least one embodiment. While the disclosure will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the disclosure to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the disclosure as defin