Acoustic Multi-Modality Inversion for Cement Integrity
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Solution Overview
Problem
Current acoustic measurements for well zonal isolation diagnosis, such as ultrasonic and sonic scans, face limitations in accurately determining cement integrity due to sensitivity to various environmental and structural factors, leading to ambiguous results, especially in multi-casing configurations where the number of unknowns increases.
Innovation Solution
An integrated inversion method combining high-frequency ultrasonic and low-frequency sonic measurements to provide a comprehensive and unambiguous diagnosis of cement properties and bond conditions in the annular space, leveraging the strengths of each modality to reduce ambiguity and uncertainty.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If single-modality acoustic measurements (ultrasonic or sonic) are used for cement integrity diagnosis, then the measurement process is simple, but the diagnosis accuracy and reliability are insufficient due to ambiguous results
Solution Approach 1:
The patent combines ultrasonic and sonic acoustic measurements into a single integrated measurement system. The ultrasonic module provides high-frequency data for near-casing cement characterization, while the sonic module provides low-frequency data for deeper formation penetration. By merging these two modalities, the system achieves comprehensive cement integrity diagnosis that overcomes the limitations of single-modality measurements, resolving the ambiguity in diagnosis results without requiring separate measurement campaigns.
Solution Approach 2:
The acoustic tool is designed with multi-functionality, incorporating both ultrasonic and sonic measurement capabilities in a single device. This universal tool can perform multiple functions: ultrasonic pulse-echo for bond quality assessment, ultrasonic pitch-catch for cement properties, sonic full-waveform for deep formation characterization, and integrated inversion for comprehensive cement evaluation. This multi-functional design improves measurement precision while managing device complexity through integration.
2Loss of information
If multiple acoustic measurements are used to probe deeper into the annular space, then more information about cement properties is obtained, but the inversion accuracy becomes sensitive to borehole fluid impedance and other environmental factors
Solution Approach 1:
The patent utilizes parameter changes across different frequency ranges. Ultrasonic measurements (high frequency) are sensitive to near-casing cement properties and bond quality, while sonic measurements (low frequency) penetrate deeper and are less sensitive to borehole fluid impedance. By incorporating measurements across this frequency spectrum, the system obtains complete cement property information while the low-frequency sonic data provides stability to the inversion process against environmental factor sensitivity.
Solution Approach 2:
The integrated inversion framework acts as an intermediary that reconciles data from ultrasonic and sonic measurements. The framework combines the high-frequency ultrasonic data (sensitive to bond quality) with low-frequency sonic data (less sensitive to fluid impedance) in a unified inversion process. This intermediary processing step harmonizes the complementary information from both modalities, reducing the sensitivity to borehole fluid impedance while maintaining complete cement property characterization.
3Measurement precision
If ultrasonic pulse-echo measurements are used at normal incidence, then cement acoustic impedance can be estimated, but the measurement cannot probe deeper than the immediate casing-cement region and is highly sensitive to borehole fluid impedance
Solution Approach 1:
The patent segments the measurement function into two complementary parts: ultrasonic pulse-echo for shallow near-casing cement characterization (providing accurate bond quality and acoustic impedance), and sonic full-waveform for deep formation penetration. Each modality is optimized for its specific depth range, with ultrasonic handling the immediate casing-cement region and sonic extending into the deeper formation. This segmentation resolves the penetration depth limitation while preserving the accurate impedance estimation capability.
4Reliability
If the number of acoustic transducers and measurement modes is increased to reduce ambiguity, then diagnosis robustness improves, but the device complexity and data processing requirements increase
Solution Approach 1:
The patent merges ultrasonic and sonic measurement modalities into a single integrated tool with a unified inversion framework. Rather than using separate tools for ultrasonic and sonic measurements, the system combines them in one device, sharing common components such as the borehole environment interface, data acquisition system, and inversion processing. This merging approach improves diagnosis robustness by combining complementary measurement types while managing device complexity through shared architecture.
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
The integrated approach allows for a more robust and accurate characterization of cement integrity, enhancing the ability to diagnose hydraulic isolation and predict cement longevity, thereby improving well zonal isolation and maintenance.
Implementation Method 1
activating the acoustic tool to form acoustic waveforms
Implementation Method 2
the receiver records the acoustic waveforms
Data Source
AI summary
Apparatus and method for characterizing a barrier installed in a borehole traversing a formation including locating an acoustic tool with a receiver and a transmitter at a location in the borehole, activating the acoustic tool to form acoustic waveforms, wherein the receiver records the acoustic waveforms, and processing the waveforms to identify barrier parameters as a function of azimuth and depth along the borehole, wherein the waveforms comprise at least two of sonic signals, ultrasonic pulse-echo signals, and ultrasonic pitch-catch signals.