Pseudo Borehole Wall Image Profiles from Outcrop Photographs

The patent creates pseudo borehole wall image profiles by digitally copying and transforming outcrop photographs. The process involves cropping the photograph, duplicating it, inverting one copy, joining them together, and applying geometric transformations to simulate a cylindrical borehole view. This digital copy serves as a calibration reference without requiring physical rock cores, thereby maintaining interpretation accuracy while eliminating the high cost of core acquisition.

The patent applies geometric transformations to change the parameters of the outcrop photograph to match the cylindrical geometry of borehole walls. Specifically, the method involves cropping the photograph to a width corresponding to half the borehole perimeter, duplicating and inverting the crop, joining them to form a complete cylindrical representation, and applying radial distortion corrections. These parameter changes eliminate geometric distortions while maintaining the cost advantage of using photographs instead of physical cores.

The patent creates a universal calibration method that can be applied to any borehole location without requiring physical rock cores at each site. The pseudo borehole wall image profiles generated from outcrop photographs serve as a multi-functional calibration tool that can be used for interpreting various geological structures (fractures, bedding planes, lithological contacts) across different boreholes and depths, eliminating the need for extensive core acquisition logistics while maintaining comprehensive calibration coverage.