A good understanding of the fracture distribution and of the main mechanisms controlling fault and fracture impedance across different lithologies is key to estimating both flow properties and recovery of geofluids in fractured reservoirs. This multidisciplinary study of the Cretaceous carbonate platform of the Maiella Mountains focused on the occurrence and impedance of two main mechanical boundaries for large-scale fractured zones. Additionally, a workflow for applying the outcrop findings to the subsurface was developed.
The two identified mechanical boundary types are related to well-sorted bioclastic packstone-grainstone units and a dolomitized bed, respectively. The first type occurs within an Upper Cretaceous succession originally deposited in an open platform environment; this mechanical boundary is associated with marine flooding surfaces that occur at the bases of 50- to 80-m-thick depositional cycles. The second type is found within a Lower Cretaceous succession deposited in a more restricted environment. Through well-log analyses, both mechanical boundary types are then identified in the subsurface and used to implement the reservoir static model through the generation of vertical transmissibility multiplier arrays for large-scale faults and fractures. The latter is an essential parameter controlling vertical fluid flow in a dynamic simulation grid of fractured reservoirs.