Reservoirl study of Sarvak formation base on microfacies, diagenetic process and flow units distribation

The Sarvak Formation deposited in the North to Northeastern margin of the Arabian Platform during the Mid-Cretaceous, and is extensively encountered in the Folded Zagros of southwestern Iran. It is the most important reservoir unit after the Asmari Formation in Iran. Petrographic analysis of the drilled wells of the Kupal oil field led to recognition of in studied wells led to determination of eight microfacies that deposited in 3 sub-environments; restricted lagoon, lagoon-open marine and shoal in an interior part of Continental carbonate ramp. Petrographic studies revealed that since deposition, the Sarvak Formation experienced several diagenetic realms including marine, meteoric, burial and telogenetic diagenetic environments. Location of the studied wells shows that the relative depth of the Sarvak Formation ramp increases from the east to the west. These diagenetic successions are mainly restricted to the upper and lower parts of the Cenomanian-Turonian disconformity. Meteoric water infiltration below this Cenomanian-Turonian disconfirm boundary and related Dissolution led to development of moldic and vuggy porosity And as a result, the reservoir potential has been increase. In this study Hydraulic flow units were identified firstly using flow zone indicators and secondly using a stratigraphic modified Lorenz plot. The flow units resulting from these two methods are compared, and their close correspondence within the sequence stratigraphic framework is discussed. Base on this results six hydraulic flow units are defined as flow units 1 and 2 of the best reservoir quality and the reservoir potential reduced to the flow unit 6.