The evolution of Pig signallers in pipeline control — Online Electronics Ltd

For years, Intrusive Pig Signallers have been ever-present in the oil and gas industry. Their existence in the industry signifies their once indisputable value and function. In a world of manual checks and hands-on operations, the signallers would trip, signalling a pig's passage through the system. A field technician, would relay the message and reset the device, ensuring its readiness for the next run.

However, this system isn’t without its challenges. Aging internals, wear and tear, and occasional installation missteps meant that these devices sometimes fail to register a pig's passage. Recognising these inefficiencies, the industry began to adapt. Junction boxes equipped with relays became a standard feature, furnishing a direct line of communication to SCADA RTUs whenever the signaller tripped.

Non-intrusive signallers are leaps and bounds ahead of their predecessors. Flashing LEDs provide instantaneous local alerts, ensuring no pig passages go unnoticed. The advancements are not limited to visual indications. These signallers come with a variety of communication options. Relay outputs and Analog 4-20mA signals relay data to control rooms. Where relay input slots might be unavailable on RTUs, the MODBUS RS485 connection offers a reliable alternative, enabling not only real-time data monitoring but also allowing a deep dive into past events. This integration further aids in data logging, real-time information accessibility, and reprogramming capabilities.

One of the major challenges faced by older systems is their dependency on direct connectivity to the control room. Non-Intrusive Pig Signallers remove this constraint. Some models allow for Long Range Radio connections (LoRaWan), fortified with high-security protocols like chirp spread spectrum. Their capability to communicate over vast terrains and long distances sets them apart. And for those instances where LoRaWan might not be the best fit, Satellite Communication & GSM can be used.

While the basic function of a signaller remains consistent – to detect and communicate the passage of a pig – the manner and depth of this communication have undergone a huge change. Gone are the days of basic hall effect magnetic indications. 3-axis Magnetometers offer a multi-dimensional view of detected magnetic signals. Their advanced settings, sophisticated enough to discern between ILI tools and standard maintenance pigs, ensure that no detail is overlooked.

Ultrasonic Active pig detectors are proficient at filtering out background noise, ensuring that disturbances like sand and bubbles don't trigger false alarms. Meanwhile, Acoustic trackers, which zero in on the unique sonic patterns of a pig moving through a line, providing another layer of detection accuracy. Non-Intrusive signallers present a diverse spectrum of detection options, varied signal characteristics, enhanced communication avenues, and simplified installation procedures.

As pipelines and control systems lean heavily into digitisation, these Non-Intrusive Pig Signallers prove they are more than ready for the challenge. Seamlessly integrating with digital twin models in SCADA control systems, they stand at the forefront of data input and their compatibility with modern technological frameworks ensures they remain relevant, not just today, but well into the future. Making the switch from Intrusive to Non-Intrusive Pig Signallers signifies the oil and gas industry’s shift towards digitalisation and precision. Their evolution represents a move towards a smarter, more efficient industry future.