Background and Objective: Jahrum Formation has long been of special interest due to its wide distribution, Biostratigraphic and Lithostratigraphic differences in different areas, and the existence of hydrocarbon reserves. The purpose of this study is to investigate the More
Background and Objective: Jahrum Formation has long been of special interest due to its wide distribution, Biostratigraphic and Lithostratigraphic differences in different areas, and the existence of hydrocarbon reserves. The purpose of this study is to investigate the Jahrum Formation in the study areas, in terms of stratigraphic position (thickness and lithology) and geology (contact with upper and lower formations) and its paleontology.
Material and Methodology: The study conducted on Jahrum formation (lower and Middle Eocene) of interior Fars, Zagros. The 465 samples were collected from Gushenekan, kuh-e-Chehel Cheshme and Tong garm. Thin sections were used to study of stratigraghy, microfacies and microfossils.
Findings: According to them, two sedimentery sequences identified. The main aims of the research are Identification of the Jahrum formation borders that connected to the Asmari at the top as discotinuty and the Sachun formation at bottom as concordant.
Discussion and Conclusions: Based on this study Jahrum formation has deposited in the internal ramp and consisting two sequences. Additionaly, sedimentary environment, geochemical analysis and Paleontological ecology of the Jahrum were studied too. Also, the tectonic position of the sedimentary basin of Jahrum Formation in comparison with the adjacent basins was presented in the form of a conceptual design for the first time.
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The lower part of Lalun Formation in type section is mainly sandstone. Base on laboratory studyand observition field, lower part of Lalun Formation is incluse sub-arkose, sub-sedarenite,feldespatic sedarenite and sedarenite facies group. Main grains of these facies are More
The lower part of Lalun Formation in type section is mainly sandstone. Base on laboratory studyand observition field, lower part of Lalun Formation is incluse sub-arkose, sub-sedarenite,feldespatic sedarenite and sedarenite facies group. Main grains of these facies are quartez, rockfragments and feldespare. Sedimentary environment of lower part of Lalun Formation is MeanderyRiver. Deposites have been fining upward facies. Cross bedding, lamination and evaporite cast haveseen on this sequence.
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Cretaceous rock out crops in south east of Tehran and north west of Bibisharbanoo Mountains with120 m in thickness composed of compact white limestone rocks and light red limestone rocks withEchinoderms and Braciupods and at the end of sequence thickness white or red ca More
Cretaceous rock out crops in south east of Tehran and north west of Bibisharbanoo Mountains with120 m in thickness composed of compact white limestone rocks and light red limestone rocks withEchinoderms and Braciupods and at the end of sequence thickness white or red calcareous layer with alat of gastropods and foraminifer are completing this sequence. Field and microscopic (petrographic)studies led to tecognition 8 carbonate.Facieses A (bioclastice mudstone) with pelagic bioclasts.Facieses B (bioclastic wackston) with pelagic bioclasts.Facieses C (bioclastic packstone) with pelagic bioclasts.Facieses (A B C) indicates medium to relatively deep marine environments (open marine)Facieses D (bioclastic grindstone) and E (intraclastic grindstone )indicates high energy.Environment (barrier)Facieses F (bioclastic packs tone) with bentic bioclasts.Facieses G (bioclastic wacks tone) woth bentic bioclasts.Facieses H (peloid wacks tone) with bentic bioclast indicates lagoon environment.These facieses indicates a carbonate basinet in shape in shape homoclinal ramp.
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Abstract
In the study of the Dariyan Formation (Shoaiba Fm.) in one of the southeastern fields of the Persian Gulf, the sedimentary environment and biostratigraphy of these deposits were investigated on the cores which obtained from this formation. In the studies of th More
Abstract
In the study of the Dariyan Formation (Shoaiba Fm.) in one of the southeastern fields of the Persian Gulf, the sedimentary environment and biostratigraphy of these deposits were investigated on the cores which obtained from this formation. In the studies of the sedimentary environment, seven carbonate microfacies and one mixed carbonate-clastic microfacies were identified, which represent the deposition of the Dariyan Formation in four facies belts, including the inner ramp, middle ramp, outer ramp and deep basin. Also, uniform facies changes, the absence of rudists forming large reefs and the replacement of Lithocodium algae with them indicate the homoclinal carbonate ramp environment.
In biostratigraphic studies based on foraminifera and calcareous algae, five biozones were identified, which represent the Aptian age for this formation. By combining the geological studies, the results obtained from the routine analysis of the cores and the evaluation of petrophysical logs, the reservoir quality of this formation was also studied, which indicated the good reservoir quality in parts of these deposits and especially the layers bearing Lithocodium algae. Based on these studies, the Dariyan Formation is one of the important reservoir formations in the east of the Persian Gulf.
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