Gravel Pack Screen Damage Quantification via Baseline Signal Suppression
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Solution Overview
Problem
The existing magnetic flux leakage (MFL) tools struggle to differentiate between the natural perforations in a gravel pack screen and potential corrosion or pitting, leading to false-positive results in downhole equipment inspection.
Innovation Solution
A system and method that process MFL tool data to isolate and suppress baseline electromagnetic field measurements from the perforations, allowing for the accurate quantification of damage in gravel pack screens by distinguishing between necessary perforations and undesirable defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MFL tools are used to inspect gravel pack screens, then corrosion and pitting can be detected, but false-positive results occur due to inability to differentiate between perforations and defects
Solution Approach 1:
The inspection process is segmented into distinct phases: acquiring baseline electromagnetic field measurements from intact gravel pack screens, then acquiring measurements from screens with potential defects. By separating the baseline signal (representing normal perforations) from the defect signal, the system can differentiate between necessary perforations and harmful defects, eliminating false positives while maintaining detection accuracy.
Solution Approach 2:
The patent extracts and removes the baseline electromagnetic field signal caused by normal gravel pack screen perforations from the total measured signal. By isolating and eliminating this known baseline component, only the residual signals from actual defects (corrosion, pitting) remain, allowing accurate detection without false positives from normal screen structure.
2Measurement precision
If baseline electromagnetic field measurements are not suppressed, then all electromagnetic signals are captured, but damage quantification is inaccurate due to interference from perforation signals
Solution Approach 1:
The system performs preliminary measurement of the baseline electromagnetic field signal from intact gravel pack screens before conducting the actual inspection. This baseline measurement represents the expected signal from normal perforations and is used to counteract or suppress its interference in the subsequent defect detection process, enabling accurate damage quantification.
Solution Approach 2:
The patent performs preliminary acquisition of baseline electromagnetic field measurements from undamaged gravel pack screens prior to the actual inspection. This preliminary action establishes a reference signal that is then subtracted from measurements taken during inspection, removing the confounding effect of normal perforations and enabling precise damage quantification.
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 detection and quantification of damage in gravel pack screens, reducing false-positive results and maintaining the integrity of downhole equipment by isolating the effects of perforations from actual defects.
Implementation Method 1
a downhole tool including a measurement tool to obtain electromagnetic field measurements indicative of disturbances associated with corrosion, pitting, or other damage to the gravel pack screen
Implementation Method 2
When internal or external flaws are present (e.g., pitting, corrosion, other damage), the magnetic flux is distorted beyond the wall of the pipe and this distortion or 'flux leakage' may be measured
Data Source
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AI summary
A system and method to quantify damage to a gravel pack screen are described. The system includes a flux leakage tool to record electromagnetic field measurements at a plurality of points on the gravel pack screen. The system also includes a processor to obtain the electromagnetic field measurements recorded at the plurality of points and to suppress a baseline signal associated with electromagnetic field measurements resulting from perforations of the gravel pack screen to isolate and quantify flux leakage resulting from the damage to the gravel pack screen from flux leakage resulting from the perforations.