The high rate of false alarms in standard pipeline leak detection systems can force system operators to waste a significant amount of labour chasing down problems that do not exist. In some instances, false alarms are so prevalent that operators in the field simply turn the system off.
If a pipeline leak detection system is sucking resources or completely shut down, what is the point of even having one? Fortunately, newer technology provides an alternative.
The biggest development in recent years is known as extended real-time transient model (E-RTTM) leak detection. Basic RTTM systems have been around for decades, but were only as good as the math used to develop the model. E-RTTM is enhanced with a pattern-recognition element to filter out false alarms, provide faster leak detection and allow operators to locate the source.
The basics of E-RTTM
Traditional pipeline leak detection approaches simply compare the outlet flow volume against the inlet flow. By comparison, E-RTTM uses software to create an hydraulic model of the pipeline and then analyses a feed of real-time information – such as flow, pressure and temperature – to create a model of expected results. In other words, it determines how the pipe is supposed to behave. The software then compares expected results with actual performance so that any mismatches can be identified.
The addition of pattern recognition provides a second stage of evaluation to filter out false alarms by validating the model to determine if it fits a certain pattern i.e. for a seeping leak or a catastrophic failure. Essentially, it is a confidence check.
E-RTTM systems can be configured for a wide variety of applications across the oil, gas, water and chemical industries. This includes pipelines from oil field to refinery, pipelines from refinery to tank farm, desalinated water pipelines to cities and non-continuously pumped transport products such as jet fuel.
The business case for implementation
Until relatively recently, a system such as E-RTTM would have required specialised computer equipment. Today, with the available memory and processing speeds of most commercial computers, the functionality is far more accessible.
As a result, there is now a much better business case for investing in the technology.
E-RTTM systems can be adapted to devices already installed on a pipeline, as opposed to other systems that require a physical installation. They can also be applied just to critical areas, such as river crossings or densely populated areas, instead of the entire pipeline.
Along with leak detection, robust E-RTTM systems will support enhanced theft detection and batch tracking as well as monitoring of tightness and lifetime stress. Batch tracking is an operational benefit that typically relies on time-based estimates. The enhanced system provides real-time tracking, which makes for better scheduling and use of resources at delivery points or terminals.
Small or gradual leaks are often not covered by standard pipeline leak detection systems, as pressure and temperature changes along the pipeline can mask small losses. E-RTTM systems offer an alternative to gradual leak detection using standard pressure and temperature instrumentation.
Pipelines are also subject to stress from external influences, such as temperature extremes and mechanical shock and vibrations, which can have a major effect on their lifespan. Regulations often require operators to document and evaluate these effects. E-RTTM systems include stress monitoring of the pipeline, without the need for human interaction, to provide base data for an assessment of the remaining pipeline service life. This allows predictive maintenance planning to ensure the next necessary integrity check happens before a critical condition occurs.
Standard pipeline leak detection systems pose a wide array of problems for system operators, but the new E-RTTM technology offers significant improvements in filtering out false alarms, providing faster leak detection and allowing operators to pinpoint the source.
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