Adaptive Frequency Electromagnetic Logging for Multi-Wall Pipe Integrity
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Solution Overview
Problem
The evaluation of metal pipe integrity in oil and gas wells, particularly in wells with multiple concentric pipes, is challenging due to the need for electromagnetic waves to penetrate through multiple metal walls, leading to a tradeoff between frequency and measurement interval, which affects spatial resolution and data quality.
Innovation Solution
An electromagnetic logging tool that operates across a wide range of frequencies, adjusting operating parameters such as frequency, logging speed, and measurement interval to optimize signal quality and resolution, using numerical inversion techniques to process signals and determine pipe thickness and other parameters, with signals above a threshold frequency weighted higher to maintain spatial resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lower frequency is used to penetrate thicker total metal thickness, then penetration capability is improved, but the measurement interval required to accumulate sufficient signal cycles increases
Solution Approach 1:
The system dynamically adjusts the operating frequency based on the detected pipe thickness. When thick pipes are detected, the frequency is lowered to maintain penetration capability; when thin pipes are detected, the frequency is raised to reduce measurement interval and improve spatial resolution. This dynamic adaptation resolves the contradiction by making the frequency a variable parameter rather than a fixed one.
Solution Approach 2:
The patent changes the electromagnetic frequency parameter adaptively based on pipe thickness conditions. By modifying this key parameter according to the inspection context, the system optimizes both penetration capability and measurement efficiency, resolving the tradeoff between these two opposing requirements.
2Reliability
If a lower frequency is used to penetrate thicker total metal thickness, then penetration capability is improved, but spatial resolution deteriorates
Solution Approach 1:
The system dynamically adjusts frequency based on pipe thickness detection results. For thick pipes, lower frequencies are used to ensure penetration; for thin pipes, higher frequencies are used to maintain spatial resolution. This dynamic parameter adjustment resolves the contradiction between penetration capability and spatial resolution.
Solution Approach 2:
The patent applies different frequency characteristics locally according to the pipe thickness at each inspection location. Instead of using a single fixed frequency for the entire inspection, the system tailors the frequency selection to the local conditions, ensuring optimal penetration where needed and optimal resolution where possible.
3Measurement precision
If a higher frequency is used to improve spatial resolution, then measurement precision is improved, but the ability to penetrate thicker metal thickness decreases
Solution Approach 1:
The system dynamically selects frequency based on the detected pipe thickness. When thin pipes are detected, higher frequencies are employed to achieve better spatial resolution; when thick pipes are detected, the frequency is lowered to ensure adequate penetration. This resolves the contradiction by making frequency adaptive rather than fixed.
Solution Approach 2:
The patent changes the electromagnetic frequency parameter based on the inspection conditions. By adjusting this parameter according to pipe thickness, the system optimizes both spatial resolution and penetration capability, resolving the tradeoff between these two performance metrics.
4Productivity
If the logging speed is increased to improve productivity, then productivity is improved, but spatial resolution deteriorates due to tool movement during measurement interval
Solution Approach 1:
The system dynamically adjusts logging speed based on the operating frequency and measurement interval requirements. When lower frequencies are used for thick pipe penetration, the logging speed is reduced to maintain spatial resolution; when higher frequencies are used for thin pipes, the logging speed can be increased to improve productivity while maintaining resolution.
Solution Approach 2:
The patent implements feedback control where the measured pipe thickness and signal characteristics inform adjustments to logging speed. This feedback mechanism ensures that logging speed is optimized for both productivity and spatial resolution based on real-time measurement conditions.
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 allows for versatile and accurate assessment of pipe integrity across varying pipe thicknesses, improving data quality and reducing logging time by optimizing frequency selection and adjusting operating parameters to maintain spatial resolution.
Implementation Method 1
the electromagnetic waves have to pass through several metal walls
Implementation Method 2
measuring an electromagnetic response at multiple frequencies
Data Source
AI summary
Pipe]parameter determinations from electromagnetic logs can be improved, in accordance with various embodiments, by weighting signals with frequencies below a threshold associated with resolution degradation lower than signals with frequencies above the threshold. The threshold frequency may be determined based on a spatial resolution associated with the logging tool and a logging speed. Further embodiments are described.