Through Tubing Cement Evaluation via Borehole Resonance
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Solution Overview
Problem
Traditional cement bond log tools face challenges in evaluating cement bonding behind casing strings, especially in eccentric configurations, due to insufficient energy penetration and signal distortion caused by tubing off-centering, making it difficult to assess cement integrity and form accurate cement bonding logs.
Innovation Solution
An acoustic logging tool is used to emit shaped signals that interact with the casing and material behind it, transforming late-time signals into the frequency domain to identify resonance modes and decay rates, which are then utilized to construct a cement bonding log, even in eccentric cases, by employing neural networks for data processing and analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional CBL tool is used for through tubing cement evaluation, then the tool can measure cement bonding, but the energy penetration through tubing is insufficient and signal quality deteriorates
Solution Approach 1:
The patent employs acoustic vibration signals to excite resonance modes in the tubing-casing-cement system. By tuning the acoustic frequency to match the natural resonance frequencies of the system, the signal energy is dramatically amplified, enabling sufficient penetration through the tubing wall while maintaining high measurement precision for cement bonding evaluation.
Solution Approach 2:
The patent utilizes the transition from non-resonant signal propagation to resonant signal amplification. When the acoustic signal frequency matches the system's natural frequency, a phase-coherent resonance condition is achieved, transforming weak penetrating signals into strong, detectable resonance modes that carry information about cement bonding quality.
2Adaptability or versatility
If traditional CBL tool is used in eccentric configurations, then the tool can operate in off-center tubing, but signal distortion increases due to tubing off-centering
Solution Approach 1:
The patent explicitly addresses eccentric (asymmetric) configurations by using resonance mode analysis that is insensitive to the symmetric positioning of the tool. The resonance frequencies and decay rates of the tubing-casing-cement system remain characteristic of the cement bonding condition regardless of tool position, allowing accurate measurement in asymmetric/eccentric wellbore geometries.
Solution Approach 2:
The patent replaces traditional mechanical contact-based or direct acoustic transmission methods with resonance-based acoustic sensing. This substitution allows the system to bypass the complications of eccentric positioning, as resonance modes are intrinsic properties of the tubing-casing-cement system that can be detected regardless of the tool's radial position within the tubing.
3Measurement precision
If multiple methods and systems are used to evaluate cement bonding in eccentric cases, then measurement accuracy can be maintained, but device complexity increases
Solution Approach 1:
The patent develops a universal resonance-based acoustic logging tool that can evaluate cement bonding in both centric and eccentric configurations using the same fundamental measurement principle. The tool excites resonance modes and analyzes decay rates, providing a single multi-functional solution that eliminates the need for multiple specialized systems while maintaining measurement precision across different wellbore geometries.
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 method provides continuous, in-situ measurements of cement bonding, allowing for accurate evaluation of cement integrity and formation of reliable cement bonding logs, even in complex wellbore geometries, enhancing the assessment of well plugging and abandonment processes.
Implementation Method 1
transforming the one or more late time signals into a frequency domain. The peaks in the frequency domain identify one or more resonance modes
Data Source
AI summary
A method and system for identifying bonding between a material and tubing. The method may include disposing an acoustic logging tool in a wellbore, wherein the acoustic logging tool comprises a transmitter, a receiver, or a transceiver, broadcasting a shaped signal with the transmitter such that the shaped signal interacts with a boundary of a casing and a material and recording a result signal from the boundary with the receiver. The method may further comprise identifying a cut-off time to be applied to the result signal, transforming the result signal from a time domain to a frequency domain, selecting one or more modes sensitive to a bonding at the boundary between the casing and the material, computing a decay rate of the one or more modes that were selected based at least one or more decay curves, and converting the decay rate to a bonding log.