Improving the Petrophysical Evaluation and Fractures study of Dehram Group Formations using conventional petrophysical logs and FMI Image Log in one of the Wells of South Pars Field

Document Type: Research Paper


1 National Iranian South Oilfields Company, Department of Geology (NISOC), Ahvaz, IranPetroleum Exploration Engineering, Department of Mining and Metallurgicl Engineering, Yazd University, Yazd, Iran

2 Petroleum Exploration Engineering, Dempartment of Petroleum Engineering, Islamic Azad University, Centeral Tehran Branch, Iran


The South Pars gas field is one of the southwestern fields of Iran. This field in the Zagros sedimentary basin and consists of two Kangan and Dalan reservoirs. The Kangan and Dalan Formations belong to Dehram Group, and they are the most significant gas reservoirs in the Persian Gulf area. In this research, exploratory and production well data in the South Pars gas field were examined. Moreover, Fracture and reservoir parameters were investigated through from petrophysical logs, FMI image log, and the litholog. Additionally, according to the lithology, shale volume, presence of evaporite sediments, and porosity, the Kangan Formation to K1 and K2, and the Dalan Formation have been zoned to K3 and K4 sections. Furthermore, fractures are essential for the initial migration of hydrocarbons from the source rock to the reservoir, and this study tries to provide useful information for the future. According to FMI log analysis, about 200 Fractures have been detected in Kangan and Upper Dalan reservoir intervals in the studied well up to now. Of which, 2 breakouts, 2 tensile fractures, 4 closed fractures, 19 open fractures, 63 beddings, 2 cross beddings, 35 conductive fractures, 26 stylolites, 47 unclassified fractures have been visible in the results. The findings of this study showed that zones K2 and K4 with the highest porosity and the lowest amount of water saturation have a higher reservoir quality than zones K1 and K3 sections.  Also, the K4 zone has had the highest fracture density in comparison to other zones, which leads to increased porosity of the zone.  Ultimately, zone K2 with the least thickness (43 meters) had a lower fracture density in comparison with the K4 zone (7 conductive fissures and 2 open fractures). Also, in comparison with other zones,  it has low water saturation and high porosity and has a higher reservoir quality than K3 and K1 zones.


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