Acoustic Logging Tool Shear-Wave Velocity Ratio Determination
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Solution Overview
Problem
Existing logging tools face challenges in accurately determining shear-wave to compressional-wave velocity ratios in well casings due to interference from various wave modes created during acoustic logging, which complicates data analysis and is sensitive to errors in material parameters.
Innovation Solution
A method using a logging tool with an array of acoustic transmitters and receivers that emits acoustic signals at different angles to determine peak waveform amplitudes and calculate the shear-wave to compressional-wave velocity ratio, allowing for precise characterization of well casing properties by beamforming and combining pitch-catch and pulse-echo measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If acoustic logging tools are used to detect materials and fluids in a well, then detection capability is improved, but wave mode interference increases and data analysis complexity increases
Solution Approach 1:
The patent segments the acoustic signal analysis by separating different wave modes (compressional waves, shear waves, surface waves) and processing them through distinct computational pathways. This allows the system to handle each wave type independently, reducing the overall complexity of data analysis while maintaining comprehensive detection capability.
Solution Approach 2:
The patent introduces an intermediary processing layer that transforms raw acoustic signals into standardized wave mode components before final analysis. This intermediary step decouples the detection function from the analysis function, allowing independent optimization of each while reducing the complexity burden on the analysis stage.
2Loss of information
If multiple wave modes are created in materials and fluids during acoustic logging, then detection information increases, but interference increases and measurement accuracy decreases
Solution Approach 1:
The patent extracts and isolates specific wave mode components from the composite acoustic signal using signal processing techniques. By separating the desired wave modes from interfering ones, the system preserves useful detection information while eliminating sources of interference that degrade measurement accuracy.
Solution Approach 2:
The patent converts the potentially harmful effect of wave mode interference into a beneficial diagnostic tool by analyzing the interference patterns themselves. The presence of multiple wave modes, rather than being purely detrimental, provides additional information about material properties when properly processed and interpreted.
3Device complexity
If data interpretation relies on material parameters, then analysis is simplified, but accuracy becomes sensitive to parameter errors
Solution Approach 1:
The patent implements feedback mechanisms where the interpreted results are continuously validated against the raw acoustic data and known physical constraints. This feedback loop allows the system to detect and correct errors in material parameter estimates, reducing sensitivity to initial parameter assumptions while maintaining analytical simplicity.
Solution Approach 2:
The patent employs dynamic adjustment of material parameters during the interpretation process rather than relying on fixed, pre-assumed values. The system adapts parameter estimates based on the actual acoustic response observed, making the analysis robust to initial errors while preserving the simplicity of parameter-based interpretation methods.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the accuracy of determining shear-wave to compressional-wave velocity ratios, reducing errors in acoustic impedance calculations and improving the assessment of casing properties, such as cement quality and corrosion, by minimizing interference and relying on precise angular scans and group velocities.
Implementation Method 1
insonifying, by a first set of transmitters of the array of acoustic transmitters, a casing of the well with a plurality of acoustic signals
Implementation Method 2
receiving, by a first set of receivers of the array of acoustic receivers, respective reflection signals corresponding to the plurality of acoustic signals
Implementation Method 3
determining, by the logging tool, respective peak waveform amplitudes associated with the respective reflection signals
Implementation Method 4
determining, by the logging tool based at least in part on the respective peak amplitudes, a velocity ratio associated with a casing of the cased well. The velocity ratio includes a ratio of a shear-wave velocity associated with the casing to a compressional-wave velocity associated with the casing
Data Source
AI summary
Systems, methods, and computer-readable media for determining shear-wave to compressional-wave velocity ratios in well casings are provided. A logging tool may include one or more acoustic phased arrays, such as one or more transmitter arrays and one or more receiver arrays each having multiple transducer elements. Peak pulse amplitudes may be calculated from received acoustic signals, and the group velocity of the peak mode may be calculated. The peak amplitude from measurements over a suitable incidence angle range may be used to determine the value of the shear-wave to compressional-wave velocity ratio.