Sedimentology
Alireza Rostami; Mohammad Hossein Adabi; Abbas Sadeghi; Seyed Ali Moallemi
Abstract
The Dariyan Formation with the Aptian age is the youngest reservoir formation of the Upper Khami group which is important in terms of hydrocarbon reservoir potential. This formation is 135 meters thick in the Kuh-e-Mish surface section and consists of thin, thick and massive limestone, marl and shale. ...
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The Dariyan Formation with the Aptian age is the youngest reservoir formation of the Upper Khami group which is important in terms of hydrocarbon reservoir potential. This formation is 135 meters thick in the Kuh-e-Mish surface section and consists of thin, thick and massive limestone, marl and shale. Petrographic studies led to the identification of 13 microfacies. These have been deposited in four types of depositional environments, including inner ramp, mid ramp, outer ramp and basin, in a ramp type carbonate platform. Based on petrography, lateral and vertical facies changes, 3 third-order cycles distinguished. An integrated multidisciplinary approach including, petrography, surface gamma-ray spectrometry and trace element analysis have been used for recognition of original carbonate mineralogy and stratigraphic interpretations of this succession. Geochemistry of minor and major elements reveal original aragonitic mineralogy of the Dariyan Formation. Bivariate plot of Mn versus Sr/Ca values illustrated that the Aptian carbonates were affected by semi close diagenetic system with moderate water/rock interaction. Trace elements (Fe and Mn) contents are compared with distribution of sedimentary facies and depositional sequences to investigate and correlate stratigraphic boundaries, which are determined by sequence stratigraphy in shallow marine carbonate platform of the Dariyan Formation. The elemental peaks coinciding with the sequence boundaries and elemental peaks are correlated with maximum flooding surfaces.
Sedimentology
Hamed Hazariyan; Masoumeh Kordi; Mansour Ziaii; Mehrdad Soleimani Monfared; َAhmad Yahyaei
Abstract
The sequence stratigraphic studies provide information regarding the distribution of different facies within sedimentary basins. With determining relationship between reservoir or non-reservoir facies and sequence stratigraphy, dissemination of reservoir zones can be achieved within sequence stratigraphic ...
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The sequence stratigraphic studies provide information regarding the distribution of different facies within sedimentary basins. With determining relationship between reservoir or non-reservoir facies and sequence stratigraphy, dissemination of reservoir zones can be achieved within sequence stratigraphic framework. In this paper, using petrographic studies correlated with Gamma-Ray deviation logs, the sedimentary environment, sequences and systems tracts of the Oligo-Miocene Asmari Formation were revealed in one of the Iranian oil fields. Moreover, based on the wireline logs and petrophysical analyses, the factors controlling reservoir quality including porosity, water saturation and shale volume were invistigated within sequences and their systems tracts. The study showed that in general, the highstand systems tracts have higher reservoir quality than the trangressive systems tracts. Distribution of grain-suported and nearshore facies and also absence of anhydrite facies in the upper parts of transgressive systems tracts and the lower parts of highstand systems tracts resulted in development of the best reservoir quality zones within each sequence. This type of studies is very helpful in analysing the sedimentary basins and discovering distribution of the hydrocarbon reserves, and thus it could assist in management of risk reduction in exploration and development activities.