The Impact of Borehole Image Analysis on the Fracture and Diagenesis Characterization of a Paleozoic Carbonate Field

This study consists of the detailed analysis of 20 FMI/FMS images from the same Paleozoic field, characterized by carbonate rocks. Both primary and secondary porosities are expected, and the latter includes both fractures and vugs. The analysis revealed that both fractures and vugs are heterogeneously distributed in the field. In the Northern sector most of the wells show very little natural fractures determined, and vugs determined mostly in younger stratigraphic intervals B-D). In the Southern sector (next to the edge of the platform) most of the wells show intense deformation mostly in the A-C intervals, and vugs detected in the lower part of the succession (A-C intervals). Moreover, karsts and vugs associated with tectonic fractures are also detected in all the wells, indicating a possible relationship between the two structures. In the Southern sector the fractures strike parallel to the large scale E-W faults that represent the edge of the platform, which suggest that the structures are linked to each other. The stratigraphic distribution of the fractures helped confining the deformation events to a short interval, probably sin-lower part of the D interval. The different stratigraphic distribution of the vugs is probably due to the position of the vadose zone.