Microfacies, Depositional Environment, Diagenetic Processes and Their Effects on Reservoir Characterization of the Khaneh-Zu Formation in the East of Kopet Dagh Basin

This investigation is focused on the Khaneh-Zu Formation as a hydrocarbon reservoir as a point of view of microfacies, depositional environment, diagenetic processes and their effects on reservoir characterization. This study is based on the integration of lithostratigraphy, field study and petrography of this formation in 2 surfaces (Abghad and Khaneh-Zu) and 2 subsurface sections (Chahchaheh and Afshar wells) in the Kopet-Dagh basin. According to petrographic studies, 9 microfacies has been identified which were deposited in 3 facies belts including mid ramp, outer ramp and basin. The lack of calciturbidites and gradual change of microfacies to each other indicates the deposition in a carbonate hompclinal ramp. Diagenetic processes which have been affected on the studied interval are bioturbation, micritization, cementation (blocky and drusy), compaction, dolomitization, dissolution, pyritization and silicification. Vuggy, intercrystalline and fracture are different identified types of porosity. The porosity types are non-facies selective and formed as a result of diagenetic processes include dissolution, dolomitization and fracturing. Cementation and compaction have negative effects on reservoir characteristics. Based on low porosity percentage and low permeability, the studied sections dose not show high reservoir quality since most of the pores are filled with calcite cements. Dissolution, chemical compaction as stylolite and cementation are the most important diagenetic processes in this formation that result burial diagenesis. As a matter of fact porosities in Khaneh-Zu Formation are vuggy type, and they are not connected to each other to make permeability and a good reservoir. However, this report would be able to introduce more information about sedimentary environment and diagenetic processes controller for Khaneh-zu formation in Kopeth Dagh area.