Solutions Engine

Stuck Pig

In most pigging operations, the pig, sphere, or inline inspection (ILI) tool travels smoothly from launcher to receiver. Occasionally, though, a pig will become stuck or stalled in the pipeline. Many conditions can lead to stuck pigs. Some of the more common causes are:

  • Debris, including wax, building up in front of the pig.
  • Excessive wear or mechanical damage to the pig.
  • Check valves inside the pipe that prevent the pig from passing.

TDW provides a full range of services to help Offshore Pipeline pipeline operators detect transmitter-equipped pigs that have become stuck or stalled and facilitate their removal.

Among other solutions, TDW can:

  • Pinpoint the location of the stuck pig.
  • Determine if the pig can be safely displaced.
  • Sweep the system clear, which can in some instances dislodge the pig.
  • Provide non-intrusive inline isolation or hot tapping and plugging technology to prepare the pipeline for pig removal.

In addition, TDW can help operators reduce the likelihood of stuck pipeline pigs through customized piggability studies. This analysis assesses and documents whether pigging is feasible and outlines the inline conditions that may have to be addressed before pigging can begin. With expanding regulatory requirements for inline inspection – and the fact that pigging can contribute to pipeline productivity and profitability – improving piggability is essential.

Technical assistance is available from TDW subject matter experts for special circumstances or if the path to a solution requires consultation.

STEP 3 / VIEW SOLUTIONS

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Choosing the correct solution for freeing a stuck or stalled pig begins with an assessment of pipeline conditions, including whether the Offshore Pipeline operator has flow, the length of time the pig has been stuck, and if the pig can be safely displaced using a mechanical method.

Pigging interventions include:

  • REDSKIN™ foam pig – Available in sizes from 2 inches through 24 inches, the REDSKIN foam pig can safely sweep a system and disengage stuck or stalled pigs. Not only can it negotiate short radius elbows, miter bends, and major diameter reductions, the REDSKIN pig is also bi-directional, capable of running in either direction in the pipeline.
  • OptionALL™ pig – Designed for multiple configurations, the OptionALL pig can be customized to include magnets that can attract and then move a stuck or stalled pig.

Technical assistance is available from TDW subject matter experts for special circumstances or if the path to a solution requires consultation.

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Because critical pipeline repairs often call for hot tapping and plugging (HT&P) solutions, TDW offers Emergency Pipeline Repair Systems (EPRS) that help pipeline owners and operators respond promptly to crisis situations while minimizing their risks and losses.

TDW partners with clients to develop an EPRS customized to their unique environments, products, and pipelines. The process begins with a thorough risk assessment and gap analysis that considers every aspect of their operation, from pipeline pressure to access to weather conditions. From there, TDW develops the resulting data into a custom emergency response plan.

Once the plan is in place, TDW gathers the necessary equipment, including tapping machines, high-pressure fittings, valves, and isolation systems. As long as the EPRS is active, TDW stores the supplies and keeps the equipment well maintained, up-to-date, and ready when needed.

The ability to take a proactive approach to emergency pipeline repair has proven highly valuable in the Offshore Pipeline market. A seemingly small leak or defect can easily escalate to a catastrophic situation that requires the immediate mobilization of critical materials, equipment, resources, and services.

Investing in an EPRS allows offshore pipeline owners and operators to deliver an appropriate response to emergency situations — from leaks to stuck pigs — in the shortest time possible. As a result, employees, the environment, and company assets are protected, and costly downtime is kept to a minimum.

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In certain Offshore Pipeline situations, extricating a stuck pig from a pipeline can be done through non-intrusive inline isolation. However, specific criteria must be met: what caused the pig to become stuck is understood, the line is fully piggable, and the isolation pig can be placed while bypassing the stuck pig.

Under those conditions, the pipeline section where the pig is stuck can be isolated non-intrusively and removed, with a new pipe spool installed by a diving support vessel (DSV) or lay barge.

TDW can assist operators by isolating the pipeline in a pre-determined position at full line pressure.

SmartPlug® isolation technology 

The TDW double block and monitor SmartPlug tool is a remotely controlled and operated, non-tethered, pipeline isolation system for oil and gas pipelines. It helps protects people, assets, and the environment while saving time and money compared to the temporary decommissioning of the entire pipeline. In addition, SmartPlug non-intrusive inline isolation technology enables local hydrotesting of the replaced/repaired area without affecting the integrity of the initial isolation, which can be held in place. The SmartPlug tool also allows production and flow of other lines tied in to the downstream section of the isolated pipeline to continue uninterrupted.

For situations where non-intrusive inline isolation is not possible, stuck pigs can be removed using the hot tap and STOPPLE® or STOPPLE Train isolation method.