Tracking ILI Pigs Despite Unexpected Speed Excurions
Inline inspection (ILI) of oil and gas pipelines has been common practice for asset owners since the 1970s. Historically, companies have tracked these ILI tools with field teams to confirm its location and ensure that the pig reaches the trap. While tracking a tool seems simple in concept, several misconceptions have become conventional wisdom when it comes to the challenges of pig tracking.
Before completing any run, it is important for pipeline owners to consider these myths and their validity. One common misconception about pig tracking is that speed excursions are unavoidable, and when this happens, the tool can’t be effectively tracked. While it is true that speed changes are common and sometimes unexpected, it is a misconception that the tool can’t be effectively tracked when this happens.
Any time there is a live tool in the pipeline, it is important to know its precise location and speed. Not only are ILI tools expensive to replace, but a lost or stuck pig can obstruct product flow leading to unwanted service disruptions.
Although an increase in a pig’s speed is sometimes unavoidable, a pipeline owner can take steps to ensure the tool is tracked regardless of speed increases using Advanced Pig Tracking methods, such as remote pig tracking. Remote tracking combines leading-edge above ground markers (AGMs) and Remote Tracking Units (RTU’s) that are pre-deployed before an ILI run and are used to track the pig from a central location. As a pig approaches a tracking site, the remote unit is activated to track the tool, and does not require a field technician to be on site.
If a speed excursion occurs, the remote unit can be activate quickly at the next site to track the tool. This is far less risky than traditional tracking, which would require the field trackers to chase the pig from site to site, which is dangerous in urban or high traffic areas or during inclement weather. Chasing a fast moving pig also results in missed passages as the tool gets ahead of the field teams.
Before any run, pipeline owners should evaluate all the potential risks and determine the best method of tracking a tool. If there is a reasonable chance of a speed excursion, remote tracking is significantly more reliable than traditional legacy tracking.
To learn more about when to use remote or legacy tracking, as well as the other myths of pig tracking, download our white paper here.