Single Fiber Simultaneous Distributed Measurements Using Wavelength Division Multiplexing

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Solution Overview

Problem

Existing distributed fiber optic sensing systems require multiple fibers to obtain simultaneous measurements of different parameters, increasing installation costs and reducing compatibility with existing systems.

Innovation Solution

A distributed measurement system that uses a single optical fiber with an adapter to combine and separate probe signals, allowing for simultaneous acquisition of different parameters of interest through a wavelength division multiplexer and correction for measurement errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple optical fibers are used to obtain simultaneous measurements of different parameters, then measurement capability is improved, but installation cost increases and compatibility with existing systems deteriorates

Engineering Contradiction:

Improvemeasurement capabilityVSAvoidinstallation cost

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple distributed sensing measurements (temperature, strain, vibration, acoustic) onto a single optical fiber by using multiple measuring instruments that probe different wavelengths or frequency bands. An adapter combines the probe signals from multiple instruments and separates the backscattered light, allowing simultaneous measurements of different parameters on one fiber, thereby reducing installation cost and improving compatibility with existing single-fiber infrastructure.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The optical fiber is made multi-functional by enabling it to carry multiple types of sensing measurements simultaneously. The adapter and measuring instruments are designed to handle multiple probe signals and extract multiple parameter measurements from the same fiber, making the single fiber universal for temperature, strain, vibration, and acoustic sensing applications.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If multiple measuring instruments are used to measure different parameters simultaneously, then measurement versatility is improved, but signal separation and data acquisition complexity increases

Engineering Contradiction:

Improvemeasurement versatilityVSAvoidsignal separation complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The adapter serves as an intermediary device that combines probe signals from multiple measuring instruments and separates the composite backscattered light into distinct portions for each instrument. It manages the signal routing and wavelength/frequency separation, simplifying the overall system architecture and reducing the complexity that would otherwise exist in directly connecting multiple instruments to the fiber.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If probe signals are launched simultaneously into the fiber, then measurement efficiency is improved, but signal interference and measurement precision may deteriorate

Engineering Contradiction:

Improvemeasurement efficiencyVSAvoidsignal accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The system assigns different local qualities to different probe signals by using distinct wavelengths or frequency bands for different measuring instruments. This wavelength/frequency division allows simultaneous probe signals to coexist in the fiber without interfering with each other, as each signal occupies a different spectral niche, thereby maintaining measurement precision while achieving high measurement efficiency.

Inventive Principle:

Principle #3Local quality

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 cost-effective and compatible simultaneous distributed measurements of various parameters along a single fiber optic sensor, enhancing data acquisition efficiency in applications like hydrocarbon well monitoring.

Implementation Method 1

A distributed measurement system uses a single optical fiber with an adapter to combine and separate probe signals, allowing for simultaneous acquisition of different parameters of interest through a wavelength division multiplexer

Methodology Applied

Scientific EffectWavelength division multiplexing:

Implementation Method 2

Fiber optic sensors employ the fact that environmental effects, such as pressure, strain, vibration, and temperature, can alter the amplitude, phase, frequency, spectral content, or polarization of light propagated through an optical fiber

Methodology Applied

Scientific EffectEnvironmental effects on light propagation:

Implementation Method 3

acquire measurement data from backscattered light generated in response to the probe signals

Methodology Applied

Scientific EffectBackscattering: Scattering

Data Source

PatentUS11421527B2Simultaneous distributed measurements on optical fiber

Publication Date: 2022.08.23 SCHLUMBERGER TECH CORP

AI summary

A system and technique for obtaining two or more distributed measurements from an optical sensing fiber deployed along a desired measuring path are disclosed. Interrogating probes from two or more different distributed measuring systems are combined and launched into the sensing fiber. Backscattered light generated in response to the combined interrogating probes is separated into portions and each portion is provided to a respective distributed measuring instrument. In this manner, distributed measurements corresponding to different parameters of interest, such as temperature and pressure, along the measuring path can be measured simultaneously using the same sensing fiber.