Eddy Current Defect Discrimination in Concentric Pipes
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Solution Overview
Problem
Existing corrosion inspection tools fail to provide a fast and reliable mechanism for characterizing individual defects in concentric metal pipes, as they primarily estimate overall casing thickness and do not effectively differentiate between inner and outer pipe conditions.
Innovation Solution
Employing a time-frequency spectrogram to process frequency domain eddy current measurements, allowing for the determination of defect location, size, and type within concentric pipe arrangements, using a range of frequencies for deeper penetration and real-time monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing corrosion inspection tools are used to estimate overall casing thickness, then the measurement process is simple, but the ability to differentiate between inner and outer pipe conditions is lost
Solution Approach 1:
The patent segments the measurement data by applying time-frequency spectrogram analysis to separate the responses from different concentric pipes. This transforms the mixed signal into distinct frequency components that correspond to different pipe layers, enabling individual defect characterization while managing complexity through systematic signal decomposition
Solution Approach 2:
The patent transitions from time-domain measurements to the time-frequency domain by applying spectrogram analysis. This dimensional transformation allows simultaneous observation of both temporal and frequency characteristics, providing additional information dimensions that enable differentiation between inner and outer pipe conditions
2Reliability
If a single frequency is used for inspection, then the measurement process is fast, but the penetration depth and defect detection capability are limited
Solution Approach 1:
The patent employs periodic action by using multiple frequency components in the excitation signal. Different frequencies penetrate to different depths and provide complementary information about defects at various locations, improving detection reliability while the systematic frequency sampling maintains reasonable inspection speed
Solution Approach 2:
The patent changes the frequency parameter of the inspection signal to achieve different penetration depths. By varying frequency and analyzing the spectral content, the system can detect defects at different radial positions and depths, enhancing reliability without requiring physical repositioning of the inspection tool
3Measurement precision
If detailed defect characterization is performed on concentric pipes, then the inspection accuracy improves, but the data processing time increases
Solution Approach 1:
The patent applies preliminary action by pre-processing the raw eddy current signals through time-frequency transformation before detailed defect analysis. This preliminary spectral decomposition organizes the data in a way that facilitates faster and more accurate defect characterization in subsequent processing steps
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
Enables accurate characterization of pipe defects, including differentiation between inner and outer pipe conditions, and provides real-time visualization of pipe integrity, improving the efficiency of hydrocarbon production by detecting corrosion and preventing leaks and environmental damage.
Implementation Method 1
employing a time-frequency spectrogram to process frequency domain eddy current measurements
Data Source
AI summary
An apparatus and a system, as well as methods, operable to include acquiring eddy current data from at least two concentric pipes, determining spatial frequency content of the eddy current data, and determining locations of defects in each of the pipes based on the spatial frequency content.