May mean Pipe Defectoscopy in general or specifically Electromagnetic Defectoscopy.
This term is misnomer it also covers the effects of pipe erosion (for example, sand erosion), pipe deformation and sometimes even pipe walls scaling.
See Also
Petroleum Industry / Upstream / Data Acquisition / Well & Reservoir Surveillance / Well logging / Cased-Hole Logging / Well Integrity Logging / Pipe Defectoscopy