Improving pipeline safety through continuous monitoring
01 July 2021
Safety is undisputedly a key priority for oil and gas pipeline operators. It goes without saying that an incident on a pipeline network will have devastating consequences, both to human life and to the environment. Effective monitoring is a critical part of pipeline asset management and central to a safety strategy as it is vital for keeping the networks secure from a range of threats.
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This article looks at the challenges associated with monitoring pipelines, and how innovative smart technologies are giving operators full visibility of the integrity and security of their entire pipeline network.
The importance of pipeline monitoring
In the last decade there have been a number of pipeline incidents resulting in loss of life and property. Records of fossil fuel pipeline incidents between January 2010 and November 2018 reveal that in the US alone there were 5,500 events. Such incidents included almost 300 explosions, more than 800 fires, and associated costs in damages exceeding US$4 billion. More sobering still is the human cost of these events, which left more than 125 people dead, almost 600 injured and almost 30,000 needing urgent evacuation as a result. Overall, the figures show that on average in the US alone, there is a pipeline fire every four days, which results in an explosion every eleven days, with fatalities every 26 days, and injuries every five days.
In Europe, one of the worst incidents in recent times was the rupture of a high-pressure natural gas pipeline following third party damage. Twenty-four people died at the site near Ghislenghien, Belgium, in 2004, and 150 people were hospitalised, most with severe burns, when damage to the pipeline occurred during the final stages of a car park construction project. Incidents are a problem worldwide, and in Mexico, in January 2019, a pipeline transporting gasoline and owned by Pemex, the state oil company, exploded in the town of Tlahuelilpan. The blast, which killed at least 137 people and injured dozens more, was believed by Mexican authorities to be caused by fuel thieves, who had illegally tapped the pipeline.
The challenges associated with traditional monitoring technologies
Pipeline failure can be caused by a number of factors – ruptures and leaks caused by corrosion, mechanical damage, etc. – or by theft-related events. Monitoring for these threats enables pipeline operators to improve their safety, and failure to do so adequately can easily cost an operator millions.
Due to the vulnerable nature of pipelines, which extend over long distances that also include some of the most isolated and remote regions on the planet, monitoring is a big task. Historically, monitoring for leaks has been achieved using internal based systems, such as mass balance and real time transient modelling (RTTM). However, these systems infer the presence of a leak by computing different operational conditions using computational pipeline monitoring (CPM) based systems and, as such, tend to have long detectability times and very low sensitivity to small leaks. As a result, leaks are often missed or alarms are raised when large quantities of product have already been lost.
In contrast, external based systems such as Fibre Optic Sensing take direct measurements of different response dynamics associated with the leak, such as the noise produced by the orifice leak. This provides a quicker detection of smaller amounts of product.
Right-of-way surveillance for theft detection is also very difficult in remote locations under extreme conditions. Line walkers and aerial surveillance can be useful, but they don’t provide continuous detection of events. As a result, large sections of pipeline in remote locations might be entirely unmonitored and extremely vulnerable to accidental damage or even criminal threats for large periods of time.
Indeed, the efficacy of traditional pipeline monitoring systems has been found to be lacking. Assessments of commonly used systems in the US has found that leak detection systems were less than 20% effective, while data from European pipeline incidents revealed that the majority of leaks were discovered through means other than the chosen leak detection system. These figures are alarming when early leak detection plays such a crucial role in minimising the risk of an incident. The faster a leak can be identified and dealt with, the better the outcome.
There is an urgent need for a continuous monitoring solution that enables operators to detect leaks and theft attempts accurately and quickly, supporting them in efforts to improve safety.
DAS delivers continuous monitoring
The latest pipeline monitoring technologies can provide a real solution to the problem. With the ability to offer continuous monitoring and accurate detection, as well as provide instant visibility of the entirety of a pipeline network, Distributed Acoustic Sensing (DAS) can help to make significant improvements to safety, while also protecting pipeline operators from financial losses.
Using photonics, DAS technology essentially turns a fibre optic cable running alongside a pipeline network into thousands of vibration sensors, able to detect any disturbances along the length of the pipeline. The technology sends thousands of pulses of light along the fibre optic cable every second and monitors the fine pattern of light reflected back. When acoustic or vibrational energy – such as that created by a leak or by digging – creates a strain on the optical fibre, this changes the reflected light pattern. By using advanced algorithms and processing techniques, DAS analyses these changes to identify and to categorise any disturbance. Each type of disturbance has its own signature and the technology can tell an operator, in real-time, what happened, exactly where it happened and when it happened.
Accurate detection in real-time
This highly reliable technology is able to cover impressive ranges of up to 100km. With vital information about an incident being delivered within minutes or even seconds of it taking place, in practical terms this means that notification of an incident can be given before a single barrel of product has been lost.
The intelligent DAS technology can adapt the system's response depending on whether an incident occurs in a high or low risk zone, while accommodating shift patterns and areas where authorised activity may be taking place. This avoids the inconvenience of “false alarms”, and the time and cost associated with investigating them. Instead, in the event of an incident, pipeline operators can take appropriate action rapidly, with all the necessary information having been made immediately available to them.
DAS technology effectively provides an invisible smart barrier along the entire length of the pipeline, which can accurately detect and alarm leaks of different sizes and their position along and around the pipeline in real time. DAS can detect vibrations caused by liquid being forced through a pipeline rupture, or by ground displacement associated with small leaks in pipelines that would otherwise remain undetected.
If the source of a leak is a tiny orifice, it could easily remain undetected or it could take days for the location of an incident to be identified with existing CPM systems. In the time it would take to locate such a leak, many millions of barrels worth of oil could have been lost. DAS has proven that it can detect leaks as small as 20 litres per minute, raising the alarm in just 90 seconds, by which time only 30 litres will have escaped. This speed is an improvement by a significant order of magnitude to existing technology. DAS can identify oil and gas leaks from many different sized orifices, even as small as 1mm.
DAS in action
Pipeline monitoring solutions using DAS are the most reliable and advanced systems currently available, allowing operators to instantly view the integrity and security of their entire network. Using a pipeline operating system based on DAS allows operators to confidently make quick decisions, assured that they have been given all the information needed to get a clear view of the situation.
By using a DAS pipeline monitoring system, common threats to pipelines, such as vandalism, theft, and accidental damage are prevented before they even occur. Indeed, DAS is already proven worldwide, and operators who have already embraced the technology have reaped the rewards. For example, in India, a DAS monitoring system alerted the operator of digging being carried out in a specific location, which enabled the company to prevent 26 hot-tapping attempts. Meanwhile, in South America, unauthorised activity was detected near a pipeline and located to within a 10-metre range, allowing swift and efficient deployment of the security team.
DAS is the solution needed for today's pipeline management
It is clear that there is a real need for continuous pipeline monitoring systems, both for improving safety and for preventing costly loss of product. DAS is one such solution, offering continuous monitoring of pipelines, even in otherwise inaccessible regions.
Pedro Barbosa, Fotech
With impressive results already seen by those pipeline operators who have adopted the technology, DAS delivers on the key factors of instant detection, precise location identification, and overall visibility of the whole pipeline network. This means that such a monitoring system can play an active role in improving safety.
This technology can also work together with existing monitoring measures to complement them, rather than to replace them. Combining information gathered from multiple monitoring and maintenance sensors into an overarching view gives operators a detailed understanding of what is happening on the pipeline at any given moment. Operators can then respond with confidence to any events before they become major incidents and improve the safety of their networks.
About the author:
As Fotech’s Industry Sector Manager for Pipelines, Pedro Barbosa works closely with pipeline operators, EPC’s and fibre optic integrators, all over the world to develop and to deliver cutting edge Distributed Acoustic Sensing (DAS) solutions for monitoring and protecting pipelines.
Pedro’s skills combine technical, commercial and managerial expertise gained during almost 15 years in the pipeline industry, both as an engineer for a Natural Gas Transmission System Operator (REN Gasodutos in Portugal) and as a Project Manager and Business Development Manager for a pipeline In-Line Inspection service provider (T.D. Williamson). Pedro holds an MSc in Mechanical Engineering from the Instituto Superior Técnico in Portugal and is in the process of finishing his second MSc in Pipeline Engineering at Newcastle University in the UK.
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