OPERATIONS & MAINTENANCE
ABOVE: Overview of the Negative Pressure Wave System with Atmos Wave Acquisition System (AWAS) units LEFT: Thieves use a double tap to try and outwit pipeline operators. By using double taps, thieves try to ‘fool’ the system that product is not being removed from the pipeline
and cooking. It can be these small, ad hoc thefts that can have the worst consequences.
THE SOPHISTICATED THIEF Tieves are becoming more sophisticated and organised, using specialist equipment such as commercial-grade welding machines, calibrated measuring instruments, night vision goggles and vans with modified suspension or exit holes built into the floor of the vehicles. Tieves will also sample product to decide if it is the right product to steal. From a technical perspective thieves will deploy several tactics, including: pre-install the tapping point, hose,
associated valves and equipment before a pipeline is commissioned; select remote and well-hidden sites such as abandoned buildings such as farms and old factories; bury and cover the hosepipe and all other devices underground. Other tactics include opening the tapping point valves very slowly to generate small pressure change over a long time (known as the patient thieves), and maintaining the theft rate below flow meter repeatability level, e.g. 0.1% of pipeline throughput. Adding to the challenging in detecting thieves is that they often carry out the activities at night. Tey frequently steal small volumes each time or inject water into the pipeline while
taking oil out. It’s not uncommon for thieves to conduct thefts at multiple locations along the same pipeline. Tieves increasingly use dangerous techniques, including angle grinding and plastic equipment. At worst, thieves have driven stakes into pipelines and used rags to reduce the flow out of the pipeline.
All of these different tactics make it difficult for pipeline companies to detect and locate thefts quickly and accurately. Although leak detection methods have previously been used for theft detection, a more focused approach is required. Te application of the negative
pressure wave, statistical volume balance
An example of a theft event generating 1.5 bar pressure drop
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