Fiber Optic Magnetic Sensor for Downhole Monitoring
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Solution Overview
Problem
Current methods for downhole magnetic field sensing in reservoirs are limited by the sensitivity of magnetoelectric sensors and the difficulty in interfacing multiple sensors from the surface, leading to challenges in continuous flood monitoring and permanent deployment, which can disrupt production.
Innovation Solution
The use of high-sensitivity magnetoelectric sensors optically coupled to fiber optic cables, specifically employing a piezoelectric portion and a distributed feedback fiber laser sensor to measure magnetic fields, allowing for continuous, time-lapse monitoring of flood fronts without the need for electronic components that cannot withstand harsh environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional electronic sensors are used for downhole magnetic field measurement, then the sensors can detect magnetic fields, but they cannot withstand harsh downhole environments and require stoppage of production for deployment and retrieval
Solution Approach 1:
The patent replaces traditional electronic sensors with a fiber optic-based sensing system that uses the piezoelectric effect and optical modulation. The fiber optic cable and piezoelectric material substitute for electronic components, enabling permanent deployment in harsh downhole environments without requiring production stoppage for sensor retrieval or replacement.
Solution Approach 2:
The patent introduces a piezoelectric material as an intermediary between the magnetic field and the optical detection system. The piezoelectric material converts magnetic field changes into mechanical strain, which then modulates the optical properties of the fiber, enabling indirect measurement of magnetic fields through an optical intermediary system.
2Measurement precision
If multiple downhole ME sensors are deployed for flood monitoring, then comprehensive monitoring coverage is achieved, but it becomes difficult to interface with multiple sensors from the surface
Solution Approach 1:
The patent merges multiple sensing functions into a single fiber optic cable system. Multiple ME sensors along the wellbore are all coupled to the same fiber optic cable, which transmits optical signals to the surface. This consolidation allows multiple sensors to be interfaced through a single communication channel, reducing the complexity of surface equipment while maintaining comprehensive monitoring coverage.
Solution Approach 2:
The fiber optic cable serves multiple functions: it acts as both the sensing medium for magnetic field detection and the communication medium for data transmission to the surface. This multi-functional design simplifies the overall system architecture by eliminating the need for separate electronic interfacing equipment for each sensor.
3Ease of manufacture
If current coupling methods for ME sensors are used, then sensors can be deployed, but permanent deployment throughout the reservoir life cycle is not permitted
Solution Approach 1:
The patent replaces traditional electronic sensor coupling methods with an optical coupling system. The fiber optic cable provides a chemically inert and mechanically robust connection that can withstand the entire reservoir life cycle without degradation, enabling permanent deployment unlike traditional electronic interfaces that require periodic maintenance or replacement.
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 continuous, permanent monitoring of downhole magnetic fields, facilitating effective flood front tracking and reducing production disruptions, thereby enhancing reservoir management and monitoring capabilities.
Implementation Method 1
a piezoelectric portion and a distributed feedback fiber laser sensor to measure magnetic fields
Implementation Method 2
a distributed feedback fiber laser sensor to measure magnetic fields, allowing for continuous, time-lapse monitoring
Data Source
AI summary
In some embodiments, an apparatus and a system, as well as a method and an article, may operate to acquire a monitoring output from a first distributed feedback (DFB) fiber laser sensor at least partially bonded to a piezoelectric portion of a downhole device, to demodulate the monitoring output to determine a frequency shift in a lasing frequency of the DFB fiber laser sensor, and to correlate the frequency shift to a measure of magnetic field strength to determine a strength of a downhole magnetic field. Additional apparatus, systems, and methods are disclosed.