7.8.4 Use Case: Digitizing Depth-Registered Raster Well Logs

Depth registration allows for the measured depth to be derived from a given location on a printed or raster image (Figure 7.8.4-1). Advanced depth registrations may allow for obtaining additional information such as the curves present and their corresponding values at a given depth.

Digitizing is the process of converting graphical features into vector values. In the case of well logs, and in particular scanned well logs, the process involved creating depth/value pairs of the well log curves on the log from an image of the log. Digitizing is often required when the only available well log existing is in hardcopy or scanned format. As a result of well logs being created since the 1930s for millions of wells in the US alone, digitizing a log is often the only way to obtain digital values of the well log curves. Obtaining the well log curve values may be required to perform log editing, splicing or other advanced petrophysical calculations.

Figure 7.8.4-1 Registration data required to understand a digitized log image includes specifying coordinates of rectangular areas on the log.