Abstract: In at least one embodiment, a well inspection method and system is disclosed. The method includes transmitting an acoustic signal from a well inspection tool into a casing structure, receiving return signals from the casing structure to the well inspection tool, performing, using at least one processor associated with the well inspection tool, a Fast Fourier Transform (FFT) on a plurality of frequencies of the return signals to generate spectrogram data, determining entropy spectra from the spectrogram data, and determining casing loadings associated with the casing structure based at least in part on the entropy spectra.

Abstract: A system for determinations associated with pipe eccentricity in a downhole environment includes a downhole tool having first transducers to provide first shear horizontal waves to the downhole environment and second transducers to provide first Lamb waves to the downhole environment, and includes memory storing instructions and a processor to execute the instructions from the memory to cause the system to receive, using the first transducers, second shear horizontal waves returned from the downhole environment and to receive, using the second transducers, second Lamb waves returned from the downhole environment, and further to determine shear horizontal third-interface echoes (TIEs) or Lamb TIEs from the second shear horizontal waves or the second Lamb waves and to determine the pipe eccentricity of the casing based in part on the one or more of the shear horizontal TIEs or the Lamb TIEs.

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.

Abstract: Methods for determining properties of a media on an exterior of a casing in downhole systems are described. The methods include conveying a logging tool through a casing in a downhole formation, stimulating shear waves and flexural waves in the casing, obtaining a shear attenuation rate measurement and a flexural attenuation rate measurement within the casing responsive to the media on the exterior of the casing, comparing the measured shear attenuation rate and the measured flexural attenuation rate against a plurality of respective division boundary values, and determining one or more properties of the media on the exterior of the casing based on the comparison of the measured shear attenuation rate and the measured flexural attenuation rate against the plurality of respective interfaces.

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.

Abstract: A method for identifying a defect within a cement layer of a multi string wellbore includes deploying a gamma scanner into the multistring wellbore, the gamma scanner including at least one source and at least one detector, the at least one source emitting radiation into the multistring wellbore and the at least one detector receiving backscatter radiation. The method also includes obtaining, from the gamma scanner, a count rate associated with at least one region of interest of the multistring wellbore. The method further includes identifying, based at least in part on data acquired from the gamma scanner, a background profile for the multistring wellbore. The method includes removing the background profile from the count rate. The method further includes identifying, within the at least one region of interest, a defect within the cement layer.

Abstract: A computer-implemented method includes receiving a plurality of sensor signals, each signal of the plurality of sensor signals being tagged with an associated time and depth. The method also includes selecting a baseline signal. The method further includes comparing a selected sensor signal, of the plurality of sensor signals, to the baseline signal. The method also includes determining a difference between the baseline signal and the selected sensor signal exceeds a threshold. The method includes identifying, based at least in part on the difference, a feature of interest associated with the selected sensor signal.

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.

Abstract: A system for evaluation of a sheathing behind a casing of a wellbore. One or more wave generators provide at least asymmetric lamb (AL) waves through a casing having an anisotropic property in a first mode of the system, and provide at least shear horizontal acoustic (SHA) waves through the casing in a second mode that is concurrent with the first mode. A receiver receives indications associated with the SHA waves and the AL waves. At least one processor determines a quality of the sheathing behind the casing based in part on the indications associated with the SHA waves and the AL waves.

Abstract: A method is provided of inspecting a nested multi-layer structure including a first and second electrically conductive layer and a third layer disposed behind the second conductive layer. The method includes deploying a sensor device including an electromagnetic acoustic transducer to a borehole location proximate to the structure, generating a drive signal including a plurality of frequencies, applying an electrical current signal to the sensor device based on the drive signal and inducing currents in the first conductive layer that induce currents generating acoustic signals having the plurality of frequencies, detecting a first set of resonant frequencies based on received electromagnetic signals, detecting a second set of resonant frequencies based on received acoustic signals, estimating a property of the first and/or the second conductive layer based on the first set of resonant frequencies, and estimating a property of the third layer based on the second set of resonant frequencies.

Abstract: Methods for determining properties of a media on an exterior of a casing in downhole systems are described. The methods include conveying a logging tool through a casing in a downhole formation, stimulating shear waves and flexural waves in the casing, obtaining a shear attenuation rate measurement and a flexural attenuation rate measurement within the casing responsive to the media on the exterior of the casing, comparing the measured shear attenuation rate and the measured flexural attenuation rate against a plurality of respective division boundary values, and determining one or more properties of the media on the exterior of the casing based on the comparison of the measured shear attenuation rate and the measured flexural attenuation rate against the plurality of respective interfaces.

Abstract: A method is provided of inspecting a nested multi-layer structure including a first and second electrically conductive layer and a third layer disposed behind the second conductive layer. The method includes deploying a sensor device including an electromagnetic acoustic transducer to a borehole location proximate to the structure, generating a drive signal including a plurality of frequencies, applying an electrical current signal to the sensor device based on the drive signal and inducing currents in the first conductive layer that induce currents generating acoustic signals having the plurality of frequencies, detecting a first set of resonant frequencies based on received electromagnetic signals, detecting a second set of resonant frequencies based on received acoustic signals, estimating a property of the first and/or the second conductive layer based on the first set of resonant frequencies, and estimating a property of the third layer based on the second set of resonant frequencies.

Abstract: A computer-implemented method includes receiving a plurality of sensor signals, each signal of the plurality of sensor signals being tagged with an associated time and depth. The method also includes selecting a baseline signal. The method further includes comparing a selected sensor signal, of the plurality of sensor signals, to the baseline signal. The method also includes determining a difference between the baseline signal and the selected sensor signal exceeds a threshold. The method includes identifying, based at least in part on the difference, a feature of interest associated with the selected sensor signal.