Facies Analysis, Diagenesis Processes and Sedimentary Environment of Shurijeh Formation in Khangiran Gas Field

Shurijeh Formation is deposited in Kopeh Dagh sedimentary basin, and it is one of the gas reservoirs in northeastern Iran. Khangiran gas field with a northwest-southeast structure is located in the northeastern part of Khorasan Razavi province. The purpose of this study is to investigate facies, sedimentary environment and diagenetic processes that have been effective on the reservoir quality of Shurijeh Formation in the studied wells. Based on petrographic studies on thin sections of Shurijeh Formation in the studied wells, nine main rock facies including Sandy Conglomerate, Quartz Arenite, Sublitarnite, Subarcose, Quartz Wackes, Claystone/Shale, Nodular Anhydrite, Sandy Dolomudstone and Sandy Dologrenston have been identified that are located in the tidal, river, flood plain and meandering sedimentary zones. Petrographic studies of thin microscopic sections show that diagenetic processes in three marine, meteoric and burial environments have affected the Shurijeh Formation. The primary processes affected in the facies of Shurijeh Formation include cementation, bioturbation, primary dolomitization and anhydrite. Finally, using image log, petrophysical log and combining the results of thin section studies in the key well of Khangiran field, was determined that in most cases there is a good conformity between the results of image log, thin sections and petrophysical log.