Structural geological interpretations from unrolled images of drill cores

Structures hidden at depth can be assessed through drill cores recovered from them. A crucial part of petroleum geology study is to interpret structures from these cores collected from vertical and inclined drilling operations reaching different depths. We deduce analytically ideal structures in unrolled/unwrapped images of cylindrical drill cores. These structures are: (i) orthogonal and conjugate fractures, (ii) single generation periodic folds and type-1 and type-2 superposed folds, (iii) listric faults and (iv) different types of angular unconformities. The sinuous curves as found in unrolled images are not always characteristic of the structures. Therefore accurate identification of structures would require additional information, such as the drill core itself.