In-line inspection (ILI) is a common and successful way to manage the ongoing integrity of operational pipelines. However, even with thorough planning, in some instances it is unfortunate that these tools, which run in extremely harsh conditions inside the pipe, can get damaged or worse still, lodged. A lodged tool not only represents a disruption in flow but also means that normal operations may need to be suspended and the tool recovered. There are, of course options for the safe removal of a lodged tool: temporarily increasing pressure, surging the line, reversing flow or using a recovery tool to push the ILI tool from its lodged position. If efforts to dislodge the tool are unsuccessful it will then be necessary to remove the tool from the line through intervention and isolation, which first requires accurately discovering the location of the tool inside the pipeline.
This paper will review a case study about a lost, lodged ILI tool. It will cover the steps used to locate the tool, clarify reasons why the tool stopped moving, explain the different approaches to reestablishing tool movement and include discussion points sometimes overlooked during the planning stages of an ILI run. The lessons-learned will cover pipeline cleanliness expectations, tool functions and requirements, data analysis from the previous geometry run and emergency response plans for managing a lost and lodged tool. These valuable lessons-learned should be incorporated into any ILI project plan.
Keywords: In-line inspection; ILI; data analysis; emergency response