Mechanical Stratigraphy of Large-Scale Fractured Zones in Platform Carbonates (Maiella Mountains, Apennines, Italy)

Understanding the main mechanisms controlling fault and fracture impedance across different lithologies is an important factor to estimate the flow properties and recovery of geo-fluids in frac-tured reservoirs. A multidisciplinary study of the Cretaceous carbonate platform of the Maiella Moun-tains allowed concluding on the occurrence and impeding mechanism of two main mechanical boundaries for large-scale fractured zones. Additionally, a workflow for applying the outcrop findings to the subsurface has been described and illustrated. The two identified mechanical boundary types are related to porous, well-sorted bioclastic packstone/grainstone units and dolomitized layers respectively. The first type occurs within the Upper Cretaceous succession in an open platform environment, whereas the second type was found within the Lower Cretaceous deposits of a more restricted environment. Depending on its sequence strati-graphic position at/above flooding surfaces, the packstone/grainstone related mechanical boundary occurs at the base of 50-80m thick cycles. A method to record both mechanical boundary types in the subsurface with a fracture impedance of 100% through the analysis of borehole image and other well logs is described. Subsequent upscaling of the generated fracture impedance logs, the interpolation of upscaled logs and the conversion of relative fracture impedance into vertical transmissibility multipli-er arrays is finally described.