Multifiber Interrogation with Non-Reflective Delay Elements

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Solution Overview

Problem

Existing distributed fiber optic sensing systems face challenges in simultaneously addressing multiple parallel fibers without interference, particularly in applications requiring continuous or fast responses, as current methods either introduce time delays or are limited to specific fiber configurations.

Innovation Solution

A distributed measurement system that includes a non-reflective delay element between the interrogation instrument and one of the fiber optic sensors to prevent overlap in backscatter returns, allowing simultaneous addressing of multiple parallel sensors by distinguishing backscatter based on round-trip transit time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple parallel fiber optic sensors are simultaneously addressed with a single interrogation instrument, then monitoring efficiency and productivity are improved, but interference between backscatter returns from different sensors occurs

Engineering Contradiction:

Improvemonitoring efficiencyVSAvoidinterference between backscatter returns

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent divides the backscatter signal acquisition process into separate time segments for each fiber sensor. By introducing different time delays to the probe signal for each fiber, the backscatter returns from multiple fibers are separated in time, allowing the interrogation instrument to distinguish and process signals from each fiber individually without interference.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary time delays to the probe signal before it reaches each fiber sensor. The delay element introduces a predetermined time offset to signals destined for specific fibers, ensuring that backscatter returns arrive at the detector at different times. This preliminary timing adjustment prevents signal overlap and interference.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If time delays are introduced to prevent interference between sensors, then signal distinguishability is improved, but response time increases

Engineering Contradiction:

Improvesignal distinguishabilityVSAvoidresponse time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent introduces minimal time delays sufficient to prevent interference between backscatter returns from adjacent fibers. Rather than using excessive delays that would significantly slow response time, the delay is carefully calibrated to be just enough to separate the signals in time, thus maintaining fast response while achieving signal distinguishability.

Inventive Principle:

Principle #16Partial or excessive action

3Adaptability or versatility

If multiple fiber configurations (single-ended and double-ended) are supported, then adaptability is improved, but device complexity increases

Engineering Contradiction:

Improvefiber configuration compatibilityVSAvoidsystem complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent creates a universal interrogation system that can handle both single-ended and double-ended fiber configurations through a unified approach. The same delay element and timing mechanism work for all fiber types, with the system automatically adapting to the specific configuration being monitored, thus achieving multi-functionality without proportionally increasing complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 simultaneous reflectometric measurements from multiple parallel fiber optic sensors without mutual interference, facilitating continuous and fast response capabilities across various fiber configurations, including single-ended and double-ended fibers, thereby enhancing monitoring efficiency in hydrocarbon well applications.

Implementation Method 1

A non-reflective delay element is coupled between the interrogation instrument and the second sensor in order to introduce a delay sufficient to prevent an overlap in time between the backscatters returned from the first and second sensors

Methodology Applied

Scientific EffectTime delay:

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 EffectLight propagation and environmental interaction:

Implementation Method 3

distinguishing backscatter based on round-trip transit time

Methodology Applied

Scientific EffectRound-trip transit time measurement: Time of Flight

Data Source

PatentUS10067030B2Multifiber interrogation with reflectometry techniques

Publication Date: 2018.09.04 SCHLUMBERGER TECH CORP

AI summary

A system and method for simultaneously addressing multiple parallel distributed fiber optic sensors using a single interrogation instrument is disclosed. One or more of the fiber optic sensors are provided with a non-reflective delay element to prevent an overlap in time between backscatter returns from the distributed fiber optic sensors, thereby allowing the backscatter returns from each sensor to be distinguished based on round-trip transit time.