Modern logging tools for the investigation of the condition of downhole tubulars provide multiple outputs derived from an array of sensors. These sensors provide simultaneous readings and are arranged so a single set of measured data is derived from a cross-section of the casing or production tubing. Data sets are rapidly updated as the tools are run in the well providing a detailed series of depth related cross-sections.

In addition to producing conventional logs in real-time, this data can be used to generate 3D images. Until recently the images produced from array tools were limited to internal dimensions. New thickness measuring tools, together with improved software, provide thickness data which can be displayed either as an image based solely on thickness or combined with internal measurements to provide 3D pictures that are analogues of the actual metal remaining within the well. These images can be used to assess both internal and external corrosion and/ or damage.

This paper describes in outline the tools used to produce the data. It employs examples from both the testing phase and initial operational deployment of the new tools to illustrate the benefits of the image approach to displaying data.

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