Biostratigraphy, microfacies and reservoir quality of the Oligocene Qom Formation (Kharzan section, Northwest of Ardestan, Central Iran)

The Central Iran Basin is a region with unique environmental characteristics in which the Late Paleogene–Early Neogene benthic foraminifera display distinctive distributions and abundances that can assist identifying intervals best reservoir potential. Lipidocyclinid miogypsinid zonal marker taxa this be correlated those SBZ23 (European Basin), indicating an Oligocene (Chattian) age. With sedimentation of continental strata Upper Red Formation following marine succession Qom Formation, it seems last Tethyan transgression Ardestan occurred Oligocene, seaway was permanently closed during Miocene. Seven carbonate microfacies marl or silty facies were identified study area based on field investigations, textural analysis faunal assemblages. These deposited open-shelf platform lagoonal, patch-reef, open-marine belts effectively define both inner middle-shelf environments. Micritization, cementation, mechanical chemical compaction, dissolution fracturing are most important diagenetic processes controlling quality Formation. investigation these formation Kharzan section revealed associated shallow lagoonal depositional environments better than other intervals, due to fracturing.