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Leak detection using Distributed Fibre-Optic Sensing (DFOS)

Advisory and verification services

DNV is a leader in verifying distributed fibre-optic sensing (DFOS) systems for pipeline leak detection. As an independent third party, it can support in advising and verifying these technologies according to international standards and guidelines.

DNV is a leader in verifying distributed fibre-optic sensing (DFOS) systems for pipeline leak detection. These systems use light signals to measure temperature, strain, and acoustic events along a fibre-optic (FO) cable near or attached to a pipeline. These systems are called DxS, which means distributed sensing, and include DTS (distributed temperature sensing), DAS (distributed acoustic sensing), and DSS (distributed strain sensing). DNV, as an independent third party, can support in advising and verifying these technologies according to international standards and guidelines. DNV ensures the suitability, reliability, accuracy, and performance of these systems for monitoring pipeline leaks and potential sabotage threats.

Don’t let your asset integrity be compromised. Use DNV fibre optic-based monitoring advisory and verification services!

DFOS system

Distributed Fibre-Optic (FO) monitoring systems are essential for gas pipelines, especially those that transport hydrogen, which is highly flammable and explosive. FO monitoring systems can detect changes in temperature, strain, vibration, and leak location along the pipeline, and alert the operators in real time. This way, the operators can take preventive measures to avoid pipeline failure and reduce the risks of gas supply disruption, environmental damage, and insurance claims.

Benefits of pipeline monitoring system based on DxS

Some benefits and challenges of using fibre optic sensors for pipelines are:

  • Real-time leak detection and localization for faster and more accurate diagnosis and repair
  • Temperature monitoring along the whole pipeline length to prevent overheating damage
  • Strain measurement using special fibres to calculate pipeline curvature and bending stress
  • Find and monitor locations of potential corrosion sites for risk-based management of corrosion under insulation (DNV-RP-G109)
  • Pipeline asset management data for maintenance planning and risk assessment
  • Insurance cost reduction by preventing failures before they occur
  • Threat monitoring to be early warned on (unwanted) threatening activities (sabotage, earthquakes, soil subsidence)
  • It can lower the operational and maintenance costs by reducing the need for conventional sensors and instruments that may be prone to failure or damage in the subsurface environment.

DxS advisory and verification services by DNV for new-built pipelines

Feasibility study:

Offshore piping

  • Provide decision support on pipeline monitoring options for new build pipelines
  • Develop basic concept and functional requirements
  • Prepare technical specifications for:
    • Fibre optic sensing unit design options
    • Integration of fibre optic sensing unit into the pipeline route
    • Qualification and testing requirements

Commissioning and operation

By integrating the FO strain sensor in the pipeline, it is possible to obtain a fingerprint along the entire length of the pipeline. The fingerprint can be used for various purposes, such as detecting changes in mechanical pipeline condition, locating pipeline leaks, and optimizing maintenance process.

DxS advisory and verification services by DNV for existing pipelines

Damaged transportation pipelineOne way to monitor pipelines is to use fibre optic sensors that are either embedded in the pipelines or run along them. This may require checking the availability and compatibility of existing fibre optic infrastructure for different monitoring applications. The DxS system is a fibre optic monitoring solution that needs to be validated before and after deployment to:

  • ensure that the DxS system meets the quality standards agreed upon with the client
  • ensure that the DxS system is installed and commissioned properly and performs reliably and accurately.

One of the benefits of the pipeline DxS system is that it can measure the strain distribution along the pipeline and detect any changes caused by external factors such as third-party damage, de-burial, free spanning, and earthquake, among others.

Another benefit is that it can identify and locate the pipeline fault by measuring the strain signature generated by the acoustic wave of the pipe containing leakage. This requires strain measurements in the acoustic frequency domain using distributed acoustic sensing (DAS) technology.

DNV can verify the performance of the DxS system in detecting and monitoring various events that affect the pipeline during operation.

DxS advisory and verification services by DNV for CCSS and H2

Burning pipelineDistributed fibre optic sensing is a technology that has many benefits for monitoring carbon sequestration and hydrogen storage and distribution. It can provide useful data on the physical state of the CO2 or H2 system, such as the temperature, pressure, and integrity of the components. It can also detect and locate any leaks or anomalies that may affect the system performance or the environment. By doing so, it can increase the safety and efficiency of the CO2 or H2 system and improve the environmental and social acceptance of the system by ensuring its compliance with the regulations and standards. However, distributed fibre optic sensing also has some technical and regulatory challenges that need to be solved. For example, it needs fibre optic sensors and cables that can withstand the harsh conditions of the CO2 or H2 system, such as high temperature, pressure, and corrosion. It also needs a secure and reliable communication and data transmission network that can link the CO2 or H2 injection and storage site, and the control center, and that can manage the large amount of data produced by the distributed fibre optic sensing system.

Leak detectionDNV offers world-class Distributed Fibre-Optic Sensing (DFOS) advisory and verification services. Our global team of experts can support you with your projects, from testing, technology qualification, design, installation to operation and maintenance. Whether you want to monitor the temperature, strain, vibration, or acoustic signals of your pipeline leakage, monitoring CO2 and H2 (onshore/offshore) storage, we have the right skills and experience for you. The DFOS advisory and verification can help you improve the performance, reliability, and safety of your systems, as well as lower costs and environmental impacts.

Contact us today and let us know how we can assist you with your DFOS needs.

Selected references:

  • Real-time detection of faults in buried HV Cables with Fibre Optic Distributed Sensing (DAS), pre-study for a European TSO, 2019
  • Assessment of the Fibre Optic Leak Detection (FOLD) for a Eurasia operating pipeline company using DAS, 2021
  • Mohsen Kavian, et al., Failure cause analysis and prevention of subsea cable failures in a joint industry project (JIP CALM), CIGRE Session 2022- B1 Insulated Cables, paper 10538, 29 August – 02 September 2022, Paris
  • Mohsen Kavian, et al., Joint Industrial Project on subsea Cable Lifetime Monitoring (JIP CALM), 11th leading International Conference and Exhibition on Industrial Power Cables - JICABLE23, 18-22 June 2023
  • Mohsen Kavian, Learnings from a Joint Industry Project on submarine power Cable Lifetime Monitoring (JIP CALM), 7th Subsea Power Cable Installation, Reliability & Asset Management Summit, 16-19 Octobre 2023, Singapore
  • DNV, in collaboration with 30+ international partners, developed FO-monitoring system proof of concept that consists of a power cable-integrated FO-sensor unit connected to a distributed strain read-out instrument that measures the power cable deformation. The development process involved sensor concept design, sensor prototyping and testing, read-out technology verification, and full-scale testing. JIP Cable Lifetime Monitoring, TKI Wind op Zee TEHE118019, 28 November 2023 (for download link of the public report, click here)
  • DAS verification for a European HVDC interconnector, 2024

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Mohsen Kavian

Mohsen Kavian

Senior Consultant Underground & Submarine Cables

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