Evaluation of depositional environment and reservoir quality of Burgan Formation in an oilfield in the Abadan Plain

The Kazhdumi Formation is a Middle Cretaceous whose base in the Abadan plain is composed of sandstone, shale and limestone, and is equivalent to the Burgan Formation in Arab countries. In this study, we investigated the reservoir quality of one of the major oilfields of the Abadan plain using thin sections, core data such as hydrocarbon impregnation, porosity, permeability, and well logs. According to petrographic studies, 4 sedimentary microfacies and 5 lithofacies have been identified in the Burgan Formation deposited in the carbonate ramp to the Delta. Diagenesis processes include dissolution, fracture, cementation, dolomitization, condensation, glaconite, hematite and pyrite occurring in three marine, meteoric and burial environments. Among the diagenesis processes, dissolution and fracture have had a special role in enhancing reservoir quality, and cementation, dolomitization and compaction have been the most important determinants of reservoir quality studied. Core studies and wellbore diagrams show that the sandstone and carbonate facies have the highest and the lowest amount of porosity, permeability and hydrocarbon impregnation, respectively, and the Chilean facies is in terms of reservoir quality between these two facies. Quartz Arenite rock facies was identified as the main reservoir zone in the studied oil field.