EMAT Generated Guided Waves in Pipes

Pipeline integrity is a must to maintain for the oil and gas industry to avoid downtimes in case of disastrous events. Following this line, pipelines are periodically inspected to know their condition and make timely decisions for replacement or repair. Nondestructive testing thus comes into play, which employs methods that generally do not require decommissioning or dismantling of pipelines, and mature technologies exist for carrying out such tests. These inspection methods use a variety of sensor technologies based on different physical principles such as acoustic emission, ultrasonic testing using a piezoelectric or electromagnetic transducer, eddy-current, magnetic flux, to name a few. This paper gives a detailed review of the applications of electromagnetic acoustic transducer (EMAT) for guided waves (GW) ultrasonic inspection of pipelines. In addition, it discusses related applications such as ultrasonic communication over pipelines and flow-rate measurement using GWs. As observed from the literature, the subject has gained equal attention from academia and industry within the last decade, and it is, therefore, important and would be helpful to compile all the results and present open areas of research along with the current trends.