oa Fracture reactivation and diagenesis in the Asmari Reservoirs (Dezful Embayment, southwest Iran) during the Zagros Orogeny: Implications for fractured reservoirs modeling workflows

Production from the Asmari carbonates of the Dezful Embayment, southwest Iran, provides a textbook example of the dynamic behavior of fractured reservoirs. In these reservoirs, fracture modeling is therefore a key task of any characterization workflow. This study presents recent findings on the relationship between fracturing, diagenesis and folding in the Zagros Foreland Basin and their practical consequences on fractured reservoirs modeling workflows. Based on the structural description of outcrops, the synthesis of image log interpretations and the analysis of fracture filling (both in outcrop and subsurface), we first propose a chronologic framework for the fracturing events in relation to paragenetic sequence in the Asmari Formation. This emphasizes the<br>pre-folding origin of the main fracture sets affecting the formation. During these early events, the pre-Hercynian NS basement trends that affected the Arabian Plate, strongly controlled the spatial distribution of fractures. This stage of fracturing was associated to the growth of burial stylolites and successive stages of dolomite and calcite cementations. In a second stage, during folding, most of the deformation was accommodated by reactivation of pre-existing fractures. These fractures were associated with the precipitation of ferroan calcite in the exposed rocks, anhydrite in the reservoir and the first stages of hydrocarbon emplacement. A 100 x 100 square km 3-D model, which includes outcrops and reservoirs, will be discussed. Contrary to the growing use of such<br>a method to control fracture density, we advocate that it better provides a good proxy for fracture reactivation potential and associated flow paths.