Enter the IoT
“Point sensors have long played a role in monitoring pipelines in SCADA (supervisory control and data acquisition)-based architectures that monitor the pipeline at discreet locations along its path, looking at measurements such as pressure, temperature, and flow,” say Hines and Williams. “CPM (computational pipeline modeling) software can look at these measurements and provide pipeline operators with alerts when the measurements fall out of preprogrammed ‘thresholds’. These sensors are typically miles apart and transmit data over a wireless network.”
Looking ahead to the next generation of pipeline-monitoring technologies, FOSA is actively advocating for DFOS (distributed fiber optic sensing), which converts a fiber optic cable buried next to the pipeline into a fully distributed array of thousands of sensing locations that physically sense vibration or acoustics, temperature, and strain events external to the pipe. “A typical resolution for fiber optic sensing is less than 10 meters or 30 feet, which means that for a 100-mile pipeline, the fiber provides around 16,000 sensing points, all looking for the signals of leaks or intrusions on the pipeline in realtime,” explain Hines and Williams. “This density and distribution of sensing points monitoring simultaneously and persistently provides significant advantage for pipeline safety and produces a huge amount of data.”
Software provides realtime analysis of this data, making it actionable for the operator. For instance, the system might generate a leak alert tagged with a location, or it might provide the location of a pipeline inspection gauge as it passes through the pipe. It might even alert operators to the presence of a trespasser on foot or in a vehicle. Augmenting the value add are additional optical fibers within the cable that can transmit data, providing a network backbone for pipeline automation instrumentation in a high-bandwidth, high-speed ecosystem.
Hines and Williams say leak detection performance on pipelines is measured against sensitivity (the size of leak that’s detectable), reliability (the number of false alarms), accuracy (pinpointing the size and location of the leak), and robustness (the ability to withstand different operating conditions). “Technology is constantly being developed and improved against these four characteristics,” the two FOSA executives explain. “Distributed fiber optic sensing is significantly moving the needle on sensitivity, accuracy, and robustness, and, when applied correctly, (it) is extremely reliable.”
Fiber optic cables must be installed during the construction phase of the pipeline, i.e., while the trench is open. As a result, new pipelines are currently the main market for DFOS technology. New construction of pipeline infrastructure may not be the way forward, according to some industry observers, who see the existing pipeline infrastructure as sufficient for today’s demands as well as tomorrow’s. However, this isn’t to say the existing infrastructure is sufficient in its current form.
Mohammad Najafi, professor in the Dept. of Civil Engineering’s UTA (Urban Water Institute) at the University of Texas Arlington, says most of the pipeline infrastructure in the U.S., specifically for water and sewer, was put in place in the 1960s and 1970s, and it is nearing the end of its useful life. Najafi suggests now is the time to do something to improve these “lifelines” to prevent catastrophic failures and service interruptions. But, he says the emphasis should be on renew and replace: “The existing pipeline infrastructure spans millions of miles and definitely it requires renewal and replacement. We need more rehabilitation, renewal, (and) replacement than new installations.”
To enable rehabilitation and renewal of existing infrastructure, Najafi points to the benefits of realtime monitoring and inspection solutions leveraging satellites and IoT connectivity. “Satellites can be used for locating and monitoring cross-country pipeline operations and locations,” he says.