Petrography, sedimentary environment and reservoir potential assessment of Asmari Formation in Kilor Karim oil field in the framework of sequence stratigraphy

In order to study petrography, sedimentary environment, sequence stratigraphy and reservoir potential of Asmari Formation in Kilurkarim oil field, 5 wells from this field were analyzed. Based on the study of 800 thin sections prepared from cutting and cores, 15 carbonate microfacies were identified, which were deposited in a homoclinal carbonate ramp. Major diagenetic processes that have affected the Asmari Formation include, micritization, dolomitization, dissolution, cementation, compaction, pyritization, hematitation, and fracture. The identified diagenetic processes are the product of shallow to deep marine and meteoric diagenesis. The sum of petrographic and petrophysical studies showed that Asmari reservoir can be divided into 5 reservoir zones in the study area. Among the reservoir zones introduced, only zones No. 1 and to some extent zone No. 4 show acceptable reservoir potential. According to lithological changes, gamma log changes, vertical changes of microfacies, sequence stratigraphy of Asmari reservoir in wells No. 1 and 5 of the field was evaluated and 5 third order depositional sequences were detected. In general, the TST systems tract in the studied sequence is characterized by a slight increase in the amount of gamma log in every 5 sequences. The HST systems tract is characterized by the reduction or persistence of gamma log values along the reservoir thickness in all five separated depositional sequences. The important thing about this systems tract is the equivalence of this systems tract with the increase of reservoir potential along the reservoir.