Subsea Fiber Optic Sensing Multiplexing and Amplification
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Solution Overview
Problem
Current subsea well fiber optic sensing systems face challenges in maximizing the number of downhole sensing fibers while minimizing the number of subsea transmission fibers, leading to complexity and cost issues due to signal fidelity and quality problems caused by long transmission fibers and multiple optical connections.
Innovation Solution
The system employs enhanced backscatter fibers with higher-than-Rayleigh scattering coefficients and ultra-low loss transmission fibers, along with remote circulators and Raman amplification, to increase signal strength and reduce noise, allowing for multiple downhole sensing fibers with improved signal-to-noise ratio and efficient optical distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple downhole sensing fibers are deployed in subsea wells, then sensing coverage and data quality improve, but the number of subsea transmission fibers and optical connections increases, leading to system complexity and cost increases
Solution Approach 1:
The patent combines multiple downhole sensing fibers into a single subsea transmission fiber using wavelength division multiplexing (WDM). Each sensing fiber operates at a distinct wavelength, allowing simultaneous transmission of multiple sensing signals through one transmission fiber, thereby reducing the number of transmission fibers and optical connections required
Solution Approach 2:
The single subsea transmission fiber serves multiple functions by carrying signals from multiple downhole sensing fibers simultaneously through wavelength multiplexing. This multi-functional approach allows one transmission fiber to replace what would traditionally require multiple separate transmission fibers
2Length of stationary object
If long subsea transmission fibers are used to connect topside facilities to subsea trees, then signal transmission distance increases, but signal loss and noise accumulation increase, degrading signal fidelity
Solution Approach 1:
The patent changes the wavelength parameter of light signals to optimize transmission through long subsea fibers. By operating at specific wavelengths (e.g., 1550 nm region) where fiber attenuation is minimized, the system maintains signal fidelity over long transmission distances. Additionally, distinct wavelengths are assigned to different sensing fibers to enable multiplexing
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 enables the simultaneous use of multiple downhole sensing fibers with enhanced signal quality and reduced subsea transmission fiber count, simplifying subsea optical infrastructure and reducing costs while maintaining high data acquisition capabilities.
Implementation Method 1
enhanced backscatter fibers with higher-than-Rayleigh scattering coefficients
Implementation Method 2
Raman amplification
Data Source
AI summary
A system and method for deploying a fiber optic sensing (FOS) system. The system may include a deployment package that is marinized. The deployment package may include a connection housing for connecting the deployment package to a subsea tree, a valve disposed on the connection housing, and a chamber connected to the valve. The deployment package may also include a cap attached to an end of the chamber opposite the valve and one or more optical connections disposed within the cap. Additionally, the deployment package may include a self-propelling vehicle that is disposed within the chamber and a downhole sensing fiber connected to the self-propelling vehicle.