Magneto-Responsive Fiber Optic Sensor for Downhole Positioning
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Solution Overview
Problem
Conventional casing collar locator tools using fiber optics are prone to noise, ambiguity, and polarization fade issues, making them inaccurate and unreliable for downhole positioning in wells, and are cumbersome due to the need for significant power and electronics.
Innovation Solution
A sensor assembly that uses a magneto-responsive sensor coupled with a poled monolithic voltage responsive device, which alters the fiber optic line's light transmission in response to casing collar detection, eliminating the need for dedicated power and electronics, and incorporates intentionally imbalanced optical detection to minimize noise and ambiguity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional fiber optic interferometry detection is used for casing collar location, then power requirements are reduced, but measurement accuracy deteriorates due to noise and polarization fade
Solution Approach 1:
The patent replaces the conventional optical interferometry detection system with a magneto-responsive sensing system. The magneto-responsive sensor detects changes in magnetic field caused by casing collars, and this mechanical/magnetic detection is transduced into optical signals via the piezoelectric material. This substitution eliminates the polarization fade issues inherent in pure optical interferometry while maintaining fiber optic power advantages.
Solution Approach 2:
The patent changes the detection parameter from optical interference patterns (prone to polarization fade) to magnetic field detection (immune to polarization effects). The magneto-responsive sensor detects magnetic field changes, which are then converted to mechanical strain on the piezoelectric material, producing stable electrical signals that are transduced to optical form for transmission.
2Use of energy by moving object
If conventional optical interferometer systems are used, then power sources can be minimized, but device complexity increases due to polarization control requirements
Solution Approach 1:
The patent replaces complex optical polarization control systems with a simpler magneto-mechanical sensing system. The magneto-responsive sensor and piezoelectric transducer provide a direct physical sensing mechanism that does not require complex optical components for polarization management, thereby reducing overall system complexity while maintaining fiber optic power advantages.
3Measurement precision
If magneto-responsive sensors with piezoelectric transduction are used, then measurement accuracy improves, but device complexity increases due to additional components
Solution Approach 1:
The patent merges multiple functions into a compact integrated assembly: the magneto-responsive sensor detects magnetic field changes, the piezoelectric material transduces these to mechanical strain and then to electrical signals, and the fiber optic cable carries the signal to the surface. This integration achieves high measurement accuracy while managing device complexity through functional consolidation.
4Device complexity
If fiber optic signaling is used without polarization management, then system simplicity increases, but reliability deteriorates due to polarization fade
Solution Approach 1:
The patent substitutes magnetic field detection with optical detection, where the magneto-responsive sensor detects magnetic changes and the piezoelectric material converts this to mechanical strain that modulates the fiber optic signal. This approach maintains system simplicity by using standard fiber optic cables without requiring complex polarization management, while improving reliability by detecting magnetic field changes that are not subject to polarization fade.
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
The solution provides accurate, real-time downhole positioning with reduced noise and ambiguity, enhancing the reliability and longevity of the system while eliminating the need for extensive power sources and electronics, thus improving the feasibility of fiber optic-based casing collar location.
Implementation Method 1
a magneto-responsive sensor for detecting a physical change at a wall of the well
Implementation Method 2
a poled monolithic structure that is coupled to the sensor may obtain a voltage therefrom upon the detecting of the physical change and be dimensionally altered thereby
Implementation Method 3
A fiber optic line that is coupled to the structure may detectably affect light passing through the line in response to the altering
Data Source
AI summary
A sensor assembly for passive detections of downhole well features. Embodiments include a casing collar locator assembly that utilizes fiber optics in combination with a magneto-responsive sensor to detect casing collars and provide real-time location information in a well. The sensor may be configured to work with a poled monolithic structure that is dimensionally responsive to voltage in a way that substantially eliminates noise during detections. Additionally, the sensor may be intentionally imbalanced, utilizing multiple fibers of different lengths and multiple wavelength monitoring so as to provide enhanced directional information as well as allow operators to decipher and address circumstances of polarization fade.