In succession of a research project, the Electro-Magnetic Acoustical Transducer (EMAT) technology could be utilized to generate ultrasound for crack detection in pipelines.
The EMAT technology and smart In-Line Inspection (ILI) tools have been developed to an advanced tool kit for inspection. Today high-resolution EMAT ILI is a diagnostic tool, that provides rich information on pipeline cracking as also the type and condition of external pipeline coatings. A high number of EMAT sensors distributed and acting over the entire pipe circumference enable high-resolution mapping of the pipe wall. Ultrasonic shear-waves at different modes are generated and captured by the transducer arrangement. Acquisition of the ultrasonic reflection and transmission signal in frequency and time domain allows for spectroscopic imaging of the pipe wall. The preferred ultrasonic modes and their associated frequencies can be determined using the corresponding dispersion relation.
This contribution shows how mode selective assessments of the captured ultrasonic spectra can be used for analysis of pipeline defects. Validation of EMAT ILI as an inspection process according to API 1163 is outlined. The established exceptionally high Probability Of Detection (POD) and Identification (POI) is derived from Level I, II and III process verification assessments. Latest developments of tailored EMAT sensor kits for ILI pipeline diagnostics are given.