Stratigraphy and Palaeontology
Peiman Rajabi
Abstract
The Asmari carbonate formation in Lorestan is seen in the form of a medium to the thick limestone-rich layer of benthic foraminifera and often as a rock formation. In this study, the stratigraphic sequence of Asmari carbonate formation in the Chenareh Anticline section located in the south of Lorestan ...
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The Asmari carbonate formation in Lorestan is seen in the form of a medium to the thick limestone-rich layer of benthic foraminifera and often as a rock formation. In this study, the stratigraphic sequence of Asmari carbonate formation in the Chenareh Anticline section located in the south of Lorestan basin and Amiran Anticline section located in the middle part of Lorestan basin were studied in terms of lithology and micro biostratigraphy. The thickness of the Chenareh Section was 180 meters and the Section of Amiran Anticline was 158 meters. In total, more than 290 thin sections of both were prepared and examined in the laboratory. The results of fossil studies based on the expansion of foraminifera finally lead to the introduction and presentation of 1 Assemblage biozone in the Amiran anticline section and 3 Assemblage biozones related to the Chenareh anticline stratigraphic section. Accordingly, the age of the Asmari Formation is in the Chenareh section is Oligo-Miocene (Chattian-Bordigalian) and in the Amiran section is Miocene (Bordigalin). According to the lithostratigraphic studies, the border of the Asmari Formation in both sections of Chenareh and Amiran with Shabazan Formation is progressive-continuous and discontinuous, and in both sections of the upper boundary with Gachsaran Formation can be seen in the same way as evaporative sediments.
Sedimentology
Samira Akbarzadeh; Abdolhossein Amini; Vahid Tavakoli; Khosro Heydari
Abstract
The Oligo–Miocene Asmari Formation is the most important reservoir rocks of the Dezful embayment oil fields. This study interpret sedimentary environments and sequence stratigraphy of the Asmari Formation in Karun oil field based on changes in facies, gamma-ray log morphology and change in concentration ...
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The Oligo–Miocene Asmari Formation is the most important reservoir rocks of the Dezful embayment oil fields. This study interpret sedimentary environments and sequence stratigraphy of the Asmari Formation in Karun oil field based on changes in facies, gamma-ray log morphology and change in concentration of thorium, potassium and uranium elements of the natural gamma- ray spectrometry. In this regard, 1 evaporate, 9 carbonate facies and 1 mixed facies were recognized. The thorium to uranium ratio used to analyze the oxidation, reduction condition. Based on the vertical distribution of the facies in the sequence stratigraphy framework, three 3rd order sequences were determined. Changing the trend of logs in time reflects the decreasing trend of gamma- ray in the sequence boundary and increasing trend at maximum flooding surface. Five main morphologies including left Box Car shape, Right Box Car shape, Serrated Bell shape, Serrated Funnel shape and serrated shape have been recognized. The conformity of this morphologies with the sequence stratigraphy leads to the relationship between the Left Box Car shape with Low stand system tract, Serrated Bell shape and Right Box Car shape with Transgressive system tract and Serrated Funnel shape with High system tract.
R. Alipoor
Abstract
The Kupal oil anticline is one of the most important structures in Dezful embayment that is located in northeast of the Ahvaz city and north of the Marun oil field. Recent deposits and Lahbari member of the Aghajari formation have formed the surface outcrops, and the Asmari formation with 7 reservoir ...
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The Kupal oil anticline is one of the most important structures in Dezful embayment that is located in northeast of the Ahvaz city and north of the Marun oil field. Recent deposits and Lahbari member of the Aghajari formation have formed the surface outcrops, and the Asmari formation with 7 reservoir layers is the main reservoir rock in this oil field. In this research fractures of the Asmari formation in this anticline have been analyzed based on well data, subsurface maps and seismic profiles. The Kupal oil anticline is a fault-related (detachment fold) and asymmetric fold, in which the middle parts have been distinguished as potential zones of of dense fractures development due to longitudinal curvature. The southwest limb in much parts and northeast limb in middle parts indicate zones with high fracture density, and the axial bending of the Kupal anticline is a result of movement of deep faults.
