The Fiji optical cable is designed for distributed temperature sensing (DTS) in pipelines, offering high-resolution, robust fiber optic monitoring for industrial applications.

Overview

The Fiji fiber optic cable is used in distributed temperature sensing (DTS) systems for pipelines, particularly in oil, gas, and LNG applications. These systems allow continuous temperature monitoring along the entire length of a pipeline, enabling leak detection, temperature profiling, and operational safety monitoring . The cable is typically non-intrusive, robust, and suitable for harsh environments, including cryogenic and high-pressure conditions.

Cable Design and Features

• Core and Sheath: The cable often includes multiple optical fibers (e.g., four-core) with Kevlar yarn reinforcement and a polyethylene sheath, providing mechanical strength and durability during installation .
• Outer Diameter: Approximately 3.5 mm, balancing flexibility and robustness for pipeline handling .
• Fiber Type: Single-mode fibers are preferred for DTS applications, compliant with ITU-T G.652/654/655 standards, ensuring low loss and high signal quality over long distances .
• Temperature and Strain Sensing: The cable supports Brillouin or Raman scattering-based DTS, allowing simultaneous measurement of temperature and strain along the pipeline .

DTS System Performance

• Spatial Resolution: Typically 2 meters, enabling precise localization of temperature changes or leaks .
• Temperature Resolution: Around 0.1°C, suitable for detecting small variations in pipeline temperature .
• Measurement Modes: Single-ended or double-ended configurations improve accuracy and calibration, with double-ended mode providing better temperature resolution .
• Monitoring Range: Long-range monitoring is possible, with single instruments covering tens of kilometers, extendable with optical amplifiers .

Applications

• Pipeline Leak Detection: Early warning for LNG or oil pipeline breaches.
• Operational Monitoring: Real-time temperature profiling during commissioning, cool-down, or normal operation.
• Structural Health Monitoring: Detecting strain or hot spots in pipelines, flowlines, and coiled tubing .
• Harsh Environments: Suitable for cryogenic LNG pipelines, high-pressure oil pipelines, and areas with electromagnetic interference .

Installation Considerations

• Cable Placement: Can be attached, embedded, or buried depending on pipeline design and environmental conditions .
• Environmental Protection: Armor and sheath selection depend on soil, temperature, and mechanical hazards.
• Integration: Compatible with DTS units like the HALOTM DTS, which provide multiplexing for multiple fiber channels and rack-mountable instrumentation .

Summary

The Fiji optical cable model is a specialized fiber optic solution for distributed temperature sensing in pipelines, combining high spatial and temperature resolution with mechanical robustness. It is suitable for long-range monitoring, leak detection, and operational safety in oil, gas, and LNG pipelines, and integrates with advanced DTS systems for real-time, continuous monitoring .