June 2021, Vol. 248, No. 6
Features
Monitoring Pipelines to Protect Against Theft, Leaks
By Pedro Barbosa, Industry Sector Manager-Pipelines, Fotech
Oil and gas pipeline operators are under enormous pressure to reduce risk across their networks while simultaneously lowering costs. This can be achieved through effectively monitoring and maintaining the integrity of the pipeline networks to minimize product loss.
Product loss typically is caused by one of two factors: theft-related events or leaks resulting from pipeline failure through corrosion or mechanical damage.
Failure to monitor against these threats adequately can easily cost an operator millions of dollars in lost fuel from leakages and stolen product. Leaks also pose a significant risk of, and the cost associated with, environmental damage to the surrounding area.
In North America alone, there were 578 reported integrity incidents, with an associated cost of more than $335 million, in 2020. Indeed, one incident on the Colonial Pipeline, originating from a crack, resulted in a leak that went undetected for days — 1.2 million gallons of product seeped into the environment.
The costs associated with the leak are estimated to be approximately $10.3 million, with at least $2.5 million expected for the environmental cleanup of the contaminated soil and groundwater.
Theft of product from hot tapping is also a key issue, and it is a growing problem worldwide. For example, in South Africa in 2020, the state-owned pipeline operator Transnet recorded more than 80 incidents of theft and attempted theft after tampering with infrastructure.
The company, which operates 23,600 miles (3,800 km) of high-pressure petroleum and gas pipelines, estimated that in one major incident, 378 barrels of crude oil were spilled into the environment following an attempted theft. There have been similar cases in South America, the Middle East, the United States, the UK, India and Mexico, among others.
Existing Monitoring
Monitoring for leaks typically is achieved using internal-based systems, which infer the presence of a leak. These systems – such as mass balance and real-time transient modeling (RTTM) – use computational pipeline monitoring (CPM) to calculate different operational conditions. However, they tend to have very low sensitivity to small leaks and long detectability times. As such, leaks often are missed, or alarms are raised when large quantities of product have already been lost.
Alternatively, external-based systems such as fiber-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.
Another external-based system is right-of-way surveillance. Here, ground patrols and aerial surveillance are used to spot any unusual activity; however, they do not provide continuous detection of events. As a result, large sections of pipeline might be entirely unmonitored and extremely vulnerable to accidental damage or even criminal threats for large periods of time.
There is a critical need for a continuous monitoring solution that enables operators to detect leaks and theft attempts more accurately and quickly, supporting the pipeline operator in its efforts for product loss prevention.
In North America, there is a common requirement to detect a leak equivalent to 1% of the flow rate of the pipeline. In a pipeline transporting 100,000 barrels of oil per day, that 1% equates to 1,000 barrels. If it takes just six hours to identify a leak, 250 barrels will have escaped.
If the leak is in an extremely isolated location, it could be many days before an operator is aware. By the time anyone arrives on the scene, hundreds of barrels will have been lost. If criminal activity was at play, the offenders will be long gone.
Clearly, speed is crucial for operators seeking to maintain their pipelines and protect their contents. Pipeline intrusion detection systems (PIDS) using advanced sensing technologies are vital here.
Acoustic Sensing
One technology that can monitor pipelines accurately for both leak detection and disturbances relating to attempted theft is distributed acoustic sensing (DAS). For example, Fotech’s LivePIPE solution uses photonic-sensing DAS technology that essentially turns a fiber-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 fiber-optic cable every second and monitors the fine pattern of reflected light. When acoustic or vibrational energy – such as that created by a leak or by digging – creates a strain on the optical fiber, this changes the reflected light pattern.
By using advanced algorithms and processing techniques, DAS analyzes these changes to identify and to categorize 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.
The 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 otherwise would remain undetected.
If the source of a leak is a tiny orifice, it easily could 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 be lost.
DAS has proven that it can detect leaks as small as 5 gallons (20 liters) per minute, raising the alarm in just 90 seconds, by which time only 8 gallons (30 liters) 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 0.04 inch (1 mm).
Real-Life Example
Detection of digging and tunneling activity is also possible through this technology. For example, during a six-month period in India, 26 separate hot-tapping incidents were detected on a single pipeline.
Most of these attempts were prevented before product was lost. Digging in the proximity of the pipeline was detected and an alarm was raised, providing timely, actionable information for operators to direct their security responses to maximum effect.
In one sophisticated attempt to steal product, a tunnel was dug from a building approximately 66 feet (20 meters) from a buried pipeline.
Working alongside a mass balance system, which located the area to within 0.3 miles (500 meters), the data meant operators were able to reduce the search area to within 33 feet (10 meters). The security team were able to find the tunnel easily and quickly.
One of the biggest priorities for pipeline operators is network integrity due to the significant environmental damage and vast costs that can result from incidents – whether malicious theft or accidental leakage.
Effective monitoring is essential for maintaining network integrity, but it poses some challenges for existing technologies.
Pipeline safety and security strategies are increasingly in need of PIDS based on DAS technology, because these systems help operators to protect their assets effectively against product loss. By gaining real-time visibility of the integrity of their entire pipeline network, operators also can protect the bottom line while reducing risk.
DAS provides a critical layer of additional intelligence, thanks to its continuous monitoring, and it can detect and pinpoint the location of multiple threats simultaneously, such as small leaks and third-party interferences.
This technology can be integrated 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 fully detailed understanding of what is happening on the pipeline at any given moment.
Only then can operators confidently maintain and respond to any events before they become major incidents.
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