Kharazmi Journal of Earth Sciences

Dalan and Kangan formations hosting major gas reservoirs in Persian Gulf Basin, are compartmentalized due to the intense facies and diagenetic changes in various scales. This means that the petroleum accumulation has been segregated into a number of individual fluid/pressure compartments. In this research by studying the sedimentology of Dalan and Kangan formations in one of the fields in the central part of the Persian Gulf, 11 microfacies related to 6 facies zone have been recognized. Based on petrographic studies, diagenetic processes affected these formations are micritization, dolomitization, cementation, stylolitization, compaction and dissolution. Then, according to sedimentological, porosity and permeability and formation pressure data, intra reservoir barriers have been identified and their potential as dynamic or static barriers have been evaluated. The results of this study show that in central part of Persian Gulf, there are 5 barriers in these formations that have the dynamic potential for reservoir compartmentalization. Anhydrite cements and chemical compaction processes are the main factors controlling pore destruction in these dynamic barriers. These barriers caused high pressure in upper Kangan and lower section of upper Dalan member. Determined dynamic barriers will have a fundamental role in field production patterns in different horizons