Sedimentary environment, diagenesis and sequence stratigraphy of Sarvak Formation in Abteymour Oilfield in Western part of the Dezful embayment

Sarvak Formation (Late Albian-Middle Turonian) is one of the important reservoir units after Asmari (Oligo-Miocene) in southwest Iran that host an important hydrocarbon reserves in this region. Due to facies and environmental variations as well as complex diagenetic history, its reservoir properties show intense complexity and heterogeneity. To understand these imposed heterogeneities a comprehensive reservoir study including facies analysis, diagenetic study and sequence stratigraphy are carried out. According to facies analysis study, carbonates of the Sarvakformation deposited in a homoclinal ramp-type platform. Low diversity of determined microfacies as well as mud-dominated facies in this field, indicating of a leeward ramp. Main diagenetic processes affected carbonates of this unit are extensive dissolution (in two step: eogenetic and telogenetic), dolomitization (in two ways: mixing zone and stylolite related), cementation (include meteoric, shallow and deep burial cements), micritization, mechanical and chemical compaction (stylolitization), dedolomitization, silicification, pyritization, recrystallization and fracturing. Paragenetic sequence of diagenetic events of this formation above and below Cenomanian-Turonian boundary showed two different histories for these two parts. Three 3rd ordered are recognized in sequence stratigraphic within the Sarvak Formation belong to Middle Cenomanian to Middle Turonian time span. Examining facies distribution patterns and diagenetic events in a sequence stratigraphic framework indicate close relationships and predictability of diagenetic alterations.