It is accepted that many situations exist on pipelines where a significant length of the pipeline (typically 2000 ft to 5 miles) is either totally inaccessible or access is so difficult or expensive that monitoring is not done at the required frequency. The need for finding a technique to allow the corrosion engineer to monitor CP levels of inaccessible locations from an accessible remote location has therefore been identified. A study to investigate all possible techniques available to achieve the above objective and to analyze typical scenarios requiring this approach has therefore been undertaken....
It is accepted that many situations exist on pipelines where a significant length of the pipeline (typically 2000 ft to 5 miles) is either totally inaccessible or access is so difficult or expensive that monitoring is not done at the required frequency. The need for finding a technique to allow the corrosion engineer to monitor CP levels of inaccessible locations from an accessible remote location has therefore been identified. A study to investigate all possible techniques available to achieve the above objective and to analyze typical scenarios requiring this approach has therefore been undertaken. Numerous techniques varying from pipe-to-soil type measurements, above ground current attenuation measurements, direct measurement of pipeline current, and measurement of the AC impedance response of the inaccessible section of pipeline were identified. In addition, some novel remote monitoring methods applicable to hostile inaccessible locations were identified. Analysis of these techniques in relation to the problem lead to the development of an algorithm to facilitate the choice of possible techniques under specific conditions.