Micro-annulus Detection via Combined Acoustic Impedance Logging
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Solution Overview
Problem
Current well logging techniques face challenges in accurately detecting micro-annuli between casing and cement in wellbores, which can lead to weakened cement bonds and potential fluid migration, increasing production costs and delaying resource recovery.
Innovation Solution
The method involves using a combination of pulse-echo and circumferential guided wave measurements to determine acoustic impedance properties, allowing for the detection of micro-annuli by comparing first and second acoustic impedance values, and employing a processor to analyze these measurements for the presence of micro-annuli between the casing and cement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional acoustic inspection methods are used to evaluate cement bond, then basic cement properties can be assessed, but micro-annuli detection accuracy is insufficient
Solution Approach 1:
The patent combines pulse-echo acoustic impedance measurements with circumferential guided wave attenuation measurements into a unified detection system. By merging these two complementary measurement techniques, the system achieves both high precision in micro-annulus detection and reliable cement bond assessment, resolving the contradiction between measurement precision and reliability.
Solution Approach 2:
The patent creates a composite evaluation approach by integrating multiple acoustic measurement modalities (pulse-echo and guided wave) that function together like composite materials. Each measurement type contributes different characteristics, and their combination produces a more accurate and reliable detection capability than either method alone could provide.
2Reliability
If multiple pressure passes are conducted to assess cement integrity, then comprehensive evaluation can be achieved, but time consumption and operational complexity increase
Solution Approach 1:
The patent merges pulse-echo and guided wave measurements into a single integrated logging process. This combination allows comprehensive cement integrity evaluation to be achieved in one pass rather than requiring multiple separate pressure passes, thereby maintaining high reliability while significantly reducing inspection time.
Solution Approach 2:
The integrated acoustic measurement system performs multiple functions simultaneously - it assesses both cement bond quality and detects micro-annuli in a single operation. This multi-functionality eliminates the need for multiple specialized passes, reducing time loss while maintaining comprehensive evaluation capability.
3Measurement precision
If single acoustic measurement method is used, then device complexity is low, but detection sensitivity for micro-annuli is insufficient
Solution Approach 1:
The patent merges two acoustic measurement methods within a single logging tool design. By integrating both pulse-echo and guided wave measurement capabilities, the device achieves high detection sensitivity for micro-annuli while managing complexity through unified system architecture and coordinated operation of the combined measurement systems.
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 and sensitivity of cement bond and micro-annulus analysis, reducing the need for multiple pressure passes and providing a more reliable assessment of cement integrity, thereby preventing fluid migration and ensuring better wellbore stability.
Implementation Method 1
transmitting an acoustic pulse incident on the casing; making a measurement of a first acoustic impedance property value from pulse-echo information generated responsive to an echo of the acoustic pulse reflected from the casing
Implementation Method 2
propagating a circumferential guided wave in the casing; making a measurement of a second acoustic impedance property value from propagating wave information generated responsive to the propagating acoustic wave
Data Source
AI summary
Methods and apparatus for inspecting oilfield infrastructure components. Methods include methods of identifying a micro-annulus outside a casing in a cemented wellbore. Methods may include transmitting an acoustic pulse incident on the casing; making a measurement of a first acoustic impedance property value from pulse-echo information generated responsive to an echo of the acoustic pulse reflected from the casing; propagating a circumferential guided wave in the casing; making a measurement of a second acoustic impedance property value from propagating wave information generated responsive to the propagating acoustic wave; and determining from the first acoustic impedance value and the second acoustic impedance value a presence of a micro-annulus between the casing and the cement.