Facies, diagenetic processes and their effect on petrophysical properties and reservoir quality of the Fahliyan Formation in Arvand Oil Field

The Fahliyan Formation in Arvand oil field has a low lithological diversity and including of limestone in the lower parts and dolostone in the upper parts of the reservoir. The goal of this study is determination of facies, depositional environment, diagenetic processes and their effect on the reservoir quality of this formation. Microscopic studies of 478 thin sections of cores led to the identification of 21 microfacies belong to 4 facies belts including tidal flat, lagoon, shoal and open marine. This study also revealed diagenetic processes including micritization, bioturbation, neomorphism, compaction, dissolution, cementation and replacement. In order to investigation of reservoir characterization, the effects of diagenetic processes and sedimentology used on the distribution of porosity and permeability. After studies of facies and diagenetic processes that affected these facies, eight petrophysical Rock Type, based on petrophysical classes of Lucia, were identified. Grainstone facies have the higher reservoir quality because of dissolution processes, packstone facies has good reservoir quality and the wackestone facies have lower reservoir quality.