The application of an electromagnetic survey technique to metal pipelines

摘要

C-Scan is an electromagnetic survey technique that has been in use since the early 1980s. An electrical current applied to a well wrapped buried metal pipeline will decrease gradually with increasing distance from the current injection point, as the current going into earth through the wrapping. C-Scan measures the strength of the signal current remaining on the line at each survey point. From this, the rate of logarithmic attenuation of the signal from any previously stored survey point can be determined to give an indication of average coating condition on the section between those points. Here, a real example of C-Scan technology applied in Shenzhen is presented in this paper. The result shows its advantages in detecting metal pipelines such as minimizing noise, high precision and efficiency.