Investigation of the relationship between reservoir rock typing, microfacies and diagenetic processes of the Sarvak Formation in one of the oil fields in Abadan plain, SW Iran

Authors

1 Ph. D., student. Dept., of Geology, Faculty of Basic Sciences, University of Hormozgan, Bandar Abbas, Iran

2 Prof., Dept., of Geology, Ferdowsi University of Mashhad, Mashhad, Iran

3 Assoc. Prof., Dept., of Geology, University of Tabriz, Tabriz, Iran

4 Assoc. Prof., Dept., of Geology, Faculty of Basic Sciences, University of Hormozgan, Bandar Abbas, Iran

5 Exploration Directorate, NIOC, Tehran, Iran

Abstract

The Sarvak formation (Cenomanian-Turonian) has one of the main stratigraphical units in SW of Iran oil fields and Abadan plain due to huge amounts of trapped oil. Investigation of Sarvak Formation based on 3 wells data including core, petrographical analysis, petrophysical logs, and POROPERM data which was received from the core laboratory, led to recognized seven microfacies in this succession. The identified facies were deposited in five sub-environments; restricted lagoon, shoal rudist biostromes, and open marine. The situation of each facies and their depositional setting proposed the homoclinal carbonate ramp platform.
Petrographical investigation shows the several diagenetic realms that affected this formation. the main diagenetic process identified in this research are, micritization, mechanical and chemical compaction, dissolution, cementation, stylolitization, dolomitization, silicification, and fracture. The depositional environment of Sarvak formation affected by a sea-level change in Cenomanian-Turonian time which is affected the reservoir section by several diagenetic phenomena. To investigate the reservoir rock typing two methods were analyzed. One of them is based on microfacies analysis and diagenetic process investigation and the other is based on RQI/FZI index. integration data and analysis show that dissolution has a positive effect, especially in grain-supported facies and cementation has a negative impact on reservoir quality index. the result of this study could be implemented in the planning of hydrocarbon exploration and development stage.

Keywords