Fracturing Style of the Asmari Formation in the Central Zagros - A Case Study from the NW Part of the Izeh Zone

Reservoir quality of the Asmari reservoirs in SW Iran is strongly affected by fractures. Therefore, fracture characterization is a key to static and dynamic modeling of these reservoirs. Generally, the available fracture data from the Asmari reservoirs are extremely poor; therefore, the Asmari outcrops can be used as a practical approach to constrain the fracture models. This paper presents new findings on fracturing style of the Asmari outcrops in NW part of the Izeh zone, using collected data at different structural domains across the Shirgun, Pabdeh and Gurpi anticlines. Fracture population was analyzed using structural techniques, and classes and origin of the common fracture sets were defined. Also, the simplified data of all domains were integrated on a synthesis map, and structurally analyzed with respect to possible controls. Structural interpretations are shown that majority of fractures had been created by different mechanisms, along with the stages of the folds growth. However, origin of few fracture sets is pre-folding. The field observations are shown that fracture attributes within different levels of the Asmari carbonate are controlled by lithology, stratigraphy, deformation, and diagenesis factors. These finding are a basis to conceptualized fold-fractures relationship that can improve fracture characterization of the Asmari reservoirs.