Study of apparent resistivity imaging testing of the corrosion of buried metal pipelines

The corrosion of buried metal pipelines can result in potentially fatal personal injuries and economic losses. In this paper, a transient electromagnetic method is used for the non-destructive testing of in-service buried metal pipelines in a trenchless state. We solve the implicit function equation to obtain the time domain apparent resistivity, which is time-depth transferred based on the smoke ring inversion theory. We then obtain a profile map of the apparent resistivity distribution of the buried medium to display the corrosion positions and the corresponding degree. The test results for the corrosion positions are verified as being generally consistent with the actual corrosion situation, only producing errors with regard to the corrosion boundary positioning. The results demonstrate that the transient electromagnetic method is a valid and practical method for testing of the corrosion of buried metal pipelines.