Remote Field Eddy Current Probe for Multi-Tubular Thickness Measurement
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Solution Overview
Problem
Existing remote field eddy current inspection techniques struggle to accurately measure thickness in multiple tubular configurations due to magnetic permeability variations caused by well intervention activities and stress changes, leading to false defect identification.
Innovation Solution
A method and system utilizing a probe with a transmitter and detectors separated by a distance greater than twice the pipe diameter, measuring phase shifts to determine pipe thickness and faults, and employing a partial saturation technique to account for permeability changes, allowing for accurate separation of thickness in multiple tubular arrangements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If remote field eddy current inspection is used in multiple tubular configurations, then thickness measurement capability is provided, but measurement precision deteriorates due to magnetic permeability variations causing false defect identification
Solution Approach 1:
The patent applies parameter changes by utilizing phase shift measurements instead of traditional amplitude-based methods. The phase shift of the eddy current signal is measured and used to determine thickness, as phase shift is less sensitive to magnetic permeability variations than amplitude. This parameter change from amplitude to phase measurement resolves the contradiction by maintaining measurement precision while improving reliability in multiple tubular configurations.
Solution Approach 2:
The patent introduces an intermediary approach by using phase shift as a mediator between the eddy current signal and thickness measurement. The phase shift serves as an intermediate parameter that is less affected by magnetic permeability variations, allowing accurate thickness measurement while filtering out false signals from permeability changes in multiple tubular arrangements.
2Ease of operation
If conventional eddy current measurement is used assuming constant magnetic permeability, then measurement simplicity is maintained, but measurement precision deteriorates due to permeability changes from well intervention activities
Solution Approach 1:
The patent changes the measurement parameter from amplitude to phase shift. This parameter change maintains ease of operation as phase shift measurement uses the same basic eddy current setup, but improves measurement precision by making the measurement less sensitive to magnetic permeability variations caused by well intervention activities like wire line operations and CCL magnets.
3Loss of information
If multiple detectors are used in multiple tubular configuration, then combined thickness information is obtained, but difficulty of detecting and measuring increases due to signal superposition
Solution Approach 1:
The patent applies parameter changes by measuring phase shift instead of amplitude for each detector. The phase shift measurements from multiple detectors provide individual thickness information for each tubular, as phase shift is directly related to the path length through the tubular wall. This resolves the information loss problem while maintaining measurement capability despite signal superposition.
Solution Approach 2:
The patent uses segmentation by having multiple detectors positioned at different locations to measure phase shift for each individual tubular. Each detector provides segmented information about a specific tubular's thickness, allowing individual measurement even in multiple tubular configurations where signals would otherwise be superimposed.
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 precise measurement of each tubular arrangement's thickness and identification of permeability-induced false responses, enhancing the reliability of pipe inspection results.
Implementation Method 1
Remote Field Eddy Current inspection techniques are commonly used to evaluate the thickness of down hole tubular
Implementation Method 2
providing a driving signal to the transmitter; receiving detector signals from the one or more detectors; determining the phase shift between the detector signals and the driving signal
Implementation Method 3
a partial saturation technique to account for permeability changes
Data Source
AI summary
In accordance with aspects of the present invention, a method of inspecting a well tubular is disclosed. The method utilizes a probe with a transmitter and detectors spaced from the transmitter by at least twice the diameter of the pipe to be tested. In some cases where multi-tubular structures are tested, the probe can include further detectors spaced from the transmitter by at least twice the diameter of the outer pipes as well. The phase of signals detected by the detectors relative to the transmitter are utilized to detect faults in the pipes.