1. Not having a scheduled pig maintenance program
Pigging is one of the most efficient ways to ensure that your pipeline is clean. Pipelines should be clear of debris, wax, scale, and other unwanted products. Starting and implementing a routine cleaning based on product and flow will improve the integrity of the pipeline.
2. Not running cleaning pigs before running an ILI tool (smart pig)
It is important to select the proper pig and to run cleaning pigs until the pipeline is clean enough for the ILI tool to run through the pipeline. The ILI tool (smart pig) records data about the integrity of the pipeline which allows the operator to find problems in the pipeline and prevent potential problems from occurring. A pig is inserted into the pipeline and is used to clean, inspect, and maintain the pipeline. Some of these operations include product removal, liquid displacement, drying, cleaning, batching, and other complex pigging solutions.
What is a pipeline pig?
“Cleaning pigs are designed to help maintain efficiency and control corrosion. Pipeline pigs for batching help prevent product contamination and mixing where there are multiple products in the line. Pigs used for displacement are designed to purge air to prepare for pipeline hydro-static testing and remove water afterwards. These kinds of pipeline pigs also used to displace hydrocarbons before repair work and to recover natural gas liquids, along with inhibiting corrosion. Gauging pigs are used for pipeline inspection, to locate pipeline damage, defects and debris.” – Pigs Unlimited https://pigsunlimited.com/mypages.php?pageid=294
Types of Pigs:
Foam Pipeline Pigs
“This pig is the most basic type of pig with the purpose of removing debris and/or liquid from the pipeline,” Pigs Unlimited . All foam pigs are designed uniquely for different purposes.
Mandrel Bodied Pigs
“This pig is designed with a metal body that can be customized with replaceable discs, cups and/or scraper brushes or gauging plates,” Pigs Unlimited. These pigs are used for long-term use, the components (cups, discs, brushes, etc.) can be replaced which makes it a new pig.
“This pig is much more flexible and is designed for cleaning, wax removal, and liquid displacement,” Pigs Unlimited. These pigs are efficient for batching, displacement, and routine pigging maintenance.
Smart Pig (ILI Tool)
A smart pig uses electronics and sensors that gathers information about the condition of the pipeline such as corrosion, cracks, or defects.
Pigs Unlimited and Inline Services has more information regarding the differences in pipeline pigs.
3. Running the tool too fast or too slow
It is critical to track the tool, stay updated with the speed of the tool, and to adjust the pressure and flow in the pipeline for accurate speed of the tool. If the pig moves too slow, it risks getting stuck in the pipeline. If the pig moves too fast, it can cause the pig to shrink and only push out some of the contents in the pipeline, not all. This circumstance usually happens with foam pigs but can happen with other pigs as well.
4. Malfunctioning pipeline equipment
It is essential to obtain and keep up with regular maintenance logs of equipment, including but not limited to pig sigs, valves, pipeline doors and other pipeline equipment.
If valves are not open properly it can damage the pig.
5. Improper loading/launching/receiving of pigs
It is vital to have written procedures for loading and launching of pigs. Although the procedures do vary based on the specific pigging system and pig used. It is still important to have procedures in case any unforeseen issues arise. Improper launching and receiving of pigs can lead to damage or danger to the pipeline and equipment; therefore, monitoring the pressure, locks, and valves are crucial.
McDonald Oilfield Operations can help your company make sure that your pipeline integrity program is compliant, flexible, and manageable. We want to ensure that your pipeline(s) and all related elements are running properly and efficiently.