Open Journal of Geology, 2016, 6, 660-671 Published Online July 2016 in SciRes. http://www.scirp.org/journal/ojg http://dx.doi.org/10.4236/ojg.2016.67051 How to cite this paper: Rezaie, P., Jooybari, A., Pour, M.M. and Gorbani, M. (2016) Factor Controlling Reservoir Properties and Flow Unit Determination in the Ilam Formation of Dezfol Embayment at Zagros Fold-Thrust Belt, Southwest of Iran. Open Journal of Geology, 6, 660-671. http://dx.doi.org/10.4236/ojg.2016.67051 Factor Controlling Reservoir Properties and Flow Unit Determination in the Ilam Formation of Dezfol Embayment at Zagros Fold-Thrust Belt, Southwest of Iran Peiman Rezaie 1* , Akram Jooybari 1 , Majid Mehdi Pour 2 , Mansour Gorbani 1 1 School of Geology, College of Science, University of Hormozgan, Bandar Abbas, Iran 2 National Iranian South Oil Company, NISOC, Ahvaz, Iran Received 26 April 2016; accepted 25 July 2016; published 28 July 2016 Copyright © 2016 by authors and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/ Abstract Dezfol embayment in the Southwest of Iran is located in the Zagros fold-thrust belt, which is one of the world’s largest petroleum provinces. Ilam Formation (Santonian-Companian) is one of the re- servoir formations in this area that has been less studied. This paper focused on reservoir proper- ties in this formation using petrography and petrophysics data. According to the petrography stu- dies Ilam Formation composed of limestone as dominant lithology. Detailed petrographic analyses, have led to identification of 10 micro-facies which are represented as a carbonate ramp deposi- tional model. Also petrographic analyses are revealed that cementation, dissolution, compaction and dolomitization are most important digenetic processes. Detailed petrographic analyses and petrophysics data showed that due to mud-supported nature of more facies (inherited low reser- voir potential from their depositional settings), diagenetic process plays an important role in in- creasing of reservoir quality. However cementation and dissolution had negative and positive ef- fects on Ilam reservoir formation, respectively. Finally at the end for better correlation and to create a flow unit, according to the petrography data and using petrophysics log, this reservoir is divided into 5 units (flow unite) by using Geolog software and then they have been correlated across the field. Keywords Component, Diagenetic Process, Flow Unit, Petrophysic, Reservoir Characterization, Ilam, Formation, Dezfol Embayment * Corresponding author.