A new version of the Vertilog flux leakage (DC Magnetic Inspection) pipe evaluation tool has been developed. This new system is called the Digital Vertilog (DV). This paper presents an explanation of the DV tool theory, operating system and its working components. The sensor system of the standard Vertilog has been provided with an updated data gathering system in order to increase the information available to the log analyst. This new system transmits true bi-polar representations of each flux leakage sensor and a number of eddy current sensors to the surface recorder. The multiple bi-polar flux leakage (FL) channels allow easier interpretation by contrasting changes due to hardware and corrosion. Some of the features more easily determined include pitting, perforation (including the phase of gun used), scratchers, and centralizers. Log examples generated in the lab and their interpretation will be presented. These examples successfully demonstrate the advantage of recording full signature wave response and accurately differentiating pipe hardware from corrosion.

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