Patent ID: 7635976

Claim:
A method of surveying a buried pipeline, which pipeline comprises a tubular member with a protective wrapping, comprising the step of selecting a plurality of spaced locations above and along the length of the pipeline, and sequentially from each spaced location applying a signal to the pipeline and measuring the signal at each of the other spaced locations, wherein the difference in measured signal strength between a pair of adjacent spaced locations along a length of the pipeline in the direction of signal transmission is a measure of the attenuation of the signal over that length of pipeline and the measurement of the signals applied to the pipeline from the plurality of spaced locations generates a plurality of measured signal strengths, the method comprising the step of calculating a plurality of attenuations for each of the plurality of lengths of pipeline located between respective pairs of spaced locations and the method further comprising the step of averaging the calculated attenuations for each length of pipeline.