Babi Cerdik

Pigging in the maintenance of pipelines refers to the practice of using pipeline inspection gauges or 'pigs' to perform various operations on a pipeline without stopping the flow of the product in the pipeline.

Intelligent pigs, also known as inline inspection (ILI) tool or smart pig, are electronic devices designed to flow on the inside of a transmission pipeline, usually while the line is in service. It is known primarily to inspect a pipeline for various types of anomalies that can increase the risks of pipeline failure.

They comprise of a combination of sophisticated electronic devices utilizing various technologies and include signal sources, sensors to detect various anomalies, onboard computer(s) to gather and collect data, and power sources to drive all the electronics. Together this equipment mounted on a pig sled can easily exceed several tons in weight, especially those tools for larger diameter pipelines. The term “intelligent pig” is utilized to differentiate the tools containing sophisticated electronics from more conventional pigs such as cleaning (i.e. poly, brush, bullet, etc.), gauging, or batch pigs that are simple mechanical devices run in pipelines for various purposes

The product in pipeline such as natural gas or crude oil pushes the pig and inspects the condition of the pipe. They have been in commercial use since 1965, primarily for the detection of wall thinning caused by ordinary corrosion. The pipeline operator is demanding intelligent pigs that could pass along multi diameter pipelines and bends, that could detect the precise location of any problem, and that does not interfere with or need the flowing material to still be operational.

There are several different technologies used in intelligent pigs to locate problems along the pipelines. Magnets have been used to detect corrosion where the most common technology is the Magnetic Flux Leakage (MFL) that detects corrosion on thinning walls. Another detection technology uses ultrasonic sensors to detect coating disbondment, cracks, dents and gouges. The MFL has been proved suitably use in gas pipeline rather than ultrasonic technology because of it attribute. MFL does not require any liquid couplant to transmit the signal for detection. The Global Positioning System (GPS) technology is being currently adapted to intelligent pigs to obtain the exact location of any problem in the pipe or to map the pipe itself.

The information which can be provided by intelligent pig covers a much wider range of inspections and troubleshooting needs rather than geometry/diameter measurement and for metal loss/corrosion detection. These include:

• Diameter/geometry measurements;
• Curvature monitoring;
• Pipeline profile;
• Temperature/pressure recording;
• Bend measurement;
• Metal-loss/corrosion detection
• Photographic inspection;
• Crack detection;
• Wax deposition measurement;
• Leak detection;
• Product sampling, and;
• Mapping

Most of pipeline operator use intelligent pigs for their pipeline integrity assessment all around the world especially in oil and gas industry. They are able to provide a much wider range of services including geometry measurement, detection of leak, temperature and pressure recording, bend measurement, wax deposition measurement, curvature monitoring, pipeline profile mapping, metal loss detection, photographic inspection and crack detection. Intelligent pigging, when properly applied, can serve as a superior inspection tool for many risks of concern over other integrity inspection methods. A proper intelligent pigging program can play a vital role in integrity management.