List of Articles Asmari formation

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  1 - Diagenesis, microfacies and determination of original carbonate mineralogy of the Asmari Formation in the southern flank of Rig anticline
   Kakemem hamid mirmohammadsadeghi
  The aim of this study is to recognize diagenetic processes, microfacies and geochemical evidence for original carbonate mineralogy of Oligocene- Miocene Asmari limestone deposited in the Rig anticline at Rig mountain oil field. In this area, the Asmari Formation with a More

  The aim of this study is to recognize diagenetic processes, microfacies and geochemical evidence for original carbonate mineralogy of Oligocene- Miocene Asmari limestone deposited in the Rig anticline at Rig mountain oil field. In this area, the Asmari Formation with a thickness of 364 m have been exposed as a sequence of thin, medium, thick, and massive carbonate rocks. Twelve microfacies types have been distinguished on the basis of depositional textures, petrographic analysis and fauna. These carbonate microfacies belong to four major sub-environments including tidal flat, lagoon, bar/ shoal, and open marine. Absence of turbidite deposits, reefal belt and gradual changes in facies indicated that the Asmari Formation was deposited in a homoclinal carbonate ramp environment. The main diagenetic processes includes: dolomitization, cementation, micritization, dissolution, and compaction. Petrographic evidence and variation of major and minor element and compare this information with modern aragonite warm water and calcitic cool to cold temperate carbonate and originally aragonite mineralogy of Ordovician sub-tropical carbonate, the calcite mineralogy of Permian sub-polar cold water of Tasmania, the Upper Jurassic aragonite Mozduran limestone, the Ilam carbonate formation, and the Fahliyan Formation indicate that original carbonate mineralogy was aragonite in the Asmari Formation. High Sr/Na ratio suggests original aragonite mineralogy. Variation of Sr and Na values versus Mn confirm replacement of aragonite by calcite during the two stages of diagenetic stabilization. The bivariate plot of Sr/Ca versus Mn shows that Asmari limestone have been influenced by meteoric diagenesis in a closed to semi-closed diagenetic system. Manuscript profile
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  2 - Rock typing in Asmari Formation using hydraulic flow unit concept, with an impact on Ahvaz Sandstone Member in Mansouri Oilfield
  مسلم  خداویسی  Kavianpour-Sangenoo  Namdarian Seyed Reza Moussavi-Harami  Mahbobi  Kadkhodaei Davood Fereidooni
  The Asmari Formation (Oligocene-Miocene) is one of the most importance reservoir rocks in the Zagros Basin. This formation in the Mansouri Oilfield is composed of the mixture of silisiclastic - carbonate deposits which silisiclastic deposits are known as the Ahwaz Sands More

  The Asmari Formation (Oligocene-Miocene) is one of the most importance reservoir rocks in the Zagros Basin. This formation in the Mansouri Oilfield is composed of the mixture of silisiclastic - carbonate deposits which silisiclastic deposits are known as the Ahwaz Sandstone Member. Rock typing is a process in which geological facies determined with their dynamic behavior. Each flow unit is related to flow zone indicator, thus zoning of a reservoir using of flow zone indicators and identification of Flow units can be used to evaluate the reservoir quality based on relationship between porosity and permeability. To evaluate the reservoir quality and determining spatial distribution of petro-physical indexes in the Asmari Formation Sandstone, porosity-permeability relationship as well as their relationship with the rock types is used and finally Flow Units and Rock Types have been identified. In this study, the Asmari Formation Sandstone is divided into four flow units A, B, C and D. Within recognized flow units, flow unit C is the best one in the terms of reservoir quality and flow unit D also has a good reservoir quality. Comparison of determined flow units with porosity logs (neutron, density and sonic), it is observed that sandstone successions of Asmari reservoir affected by diagenetic processes like fracturing, dissolution, dolomitic cementation and hydrocarbon migration before cementation and flow units C and D are more extended, so porosity logs show good reservoir quality in this interval of Asmari succession. Thus it can be deduced that using hydraulic flow units, we can determine rock types groups in wells with core and then extrapolate the results into uncored wells. Manuscript profile
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  3 - Factors controlling different types of anhydrite textures and their relation to reservoir quality in the Asmari reservoir in Ahvaz oil field
  نسترن  آزادبخت
  Various diagenetic processes have affected reservoir quality of the Asmari Formation in Ahvaz Oil Field in wells No. 19 with a thickness of 357 meters. It is composed of limestone dolomite, dolomitic limestone, sandy dolomitic limestone, sandstone, siltstone and sha More

  Various diagenetic processes have affected reservoir quality of the Asmari Formation in Ahvaz Oil Field in wells No. 19 with a thickness of 357 meters. It is composed of limestone dolomite, dolomitic limestone, sandy dolomitic limestone, sandstone, siltstone and shale. Study of 1100 thin sections from available cores at this well as well as the well’s numeral data, porosity and permeability of cores, indicates that the most important diagenetic processes is anhydritic cement with different types of textures. It appears as poikilotopic, porefilling and pervasive, nodular, fracture filling, sparce crystals, and evaporite veins. During different steps of diagenesis, these texture show replacement and pore filling porosity that have affected different facies to some degrees. Results of this study show that anhydrite cement occurs mainly in dolomitic and sandstone facies and to some extent, affected the reservoir quality. This is due to the effect of sulphate rich brines during dolomitization. Where the presence of anhydrite cements in limestone facies is sparse and rare, it has little effect on reservoir quality. However, pore filling and pervasive anhydrite texture filling all pore-space in dolograinstone and dolopackstone grain-supported facies during shallow burial intensively reduced reservoir quality. Dissolution of cements at later stage of diagenetic processes (creating secondary porosity) improved reservoir quality. In addition, solution of texture poikilotopic anhydrite in sandstone facies and repercipitated as patchy anhydrite with poikilotopic texture, results in reduction of porosity but it doesn’t make any changes in throat pores. Hence patchy anhydrite with poikilotopic texture that reduces porosity converts the sample from Lucias class 2 to class 1. Manuscript profile
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  4 - The history of deposition and post-deposition and their effects on the reservoir quality of Asmari Formation in Ahvaz oilfield
  Akbar Heidari Milad Faraji Narges Shokri
  The carbonate interval of the Asmari formation along with sandstone deposits were deposited in most areas of the Zagros sedimentary Basin, including the Ahvaz area, in Oligo-Miocene. In this study, the effects of depositional and post-depositional environments on the re More

  The carbonate interval of the Asmari formation along with sandstone deposits were deposited in most areas of the Zagros sedimentary Basin, including the Ahvaz area, in Oligo-Miocene. In this study, the effects of depositional and post-depositional environments on the reservoir quality of zone A7 of the Asmari Formation in well No. 4 in Ahvaz oil field were studied. The study of the sequences of the Asmari Formation in this section led to the identification of 11 carbonate facies, one evaporite facies, one mixed carbonate-siliciclastic facies, and one siliciclastic facies. Sedimentary environments of tidal zone, lagoon, coral reef and open sea were introduced for the depositional environment of identified facies. Due to the absence of sudden changes, it seems that the studied deposits were deposited in a ramp-type carbonate platform that was influenced by siliciclastic sediments from the Zagros river systems. The immature sedimentary texture of the sandstone facies indicates the proximity of the origin of the quartz sources to the carbonate basin. Among the diagenetic processes that have affected the examined sequences, the following processes can be mentioned: micritization, cementation, neomorphism, physical and chemical compaction, dissolution, fracture development and filling, dolomitization, and anhydritization. These diagenetic processes occurred in post-depositional marine, meteoric and burial diagenetic environments. Many fractures were filled with petroleum, which indicates that fractures, along with dolomitization, chemical compaction, and fenestral pores, are among the most important post-sedimentation complications to increase reservoir quality. While cementation and anhydritization resulted in reducing the reservoir quality by closing the pore spaces . Manuscript profile
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  5 - Reservoir quality evaluation of the Asmari Formation in the framework of sequence stratigraphy in one of the Iranian SW oilfield
  Ebrahim Sfidari A. Hakymi-Zanuz
  The Oligo-Miocene Asmari Formation forms the main reservoir rock of many Dezful Embayment fields. Microfacies analysis, diagenetic features, and sequence stratigraphic evaluation of the Asmari Formation were carried out based on the petrographic investigation, petrophys More

  The Oligo-Miocene Asmari Formation forms the main reservoir rock of many Dezful Embayment fields. Microfacies analysis, diagenetic features, and sequence stratigraphic evaluation of the Asmari Formation were carried out based on the petrographic investigation, petrophysical logs, and core measurement porosity and permeability data. Petrographic analyses led to the identification of twelve microfacies indicating five subenvironments including tidal flat, lagoon, barrier (belonging to inner ramp), middle ramp, and outer ramp, all of which are representing a homoclinal ramp. Tidal flat, lagoonal, and barrier microfacies are mostly present in the upper parts of the Asmari Formation, while middle and outer ramp microfacies were largely developed in the middle part. Cementation, compaction, dolomitization, dissolution, and fracturing are the main diagenetic processes in this formation. Compaction and cementation have negatively affected reservoir quality while fracturing, dolomitization, and dissolution contributed to reservoir quality enhancement. The sequence stratigraphic studies represent three 3rd order sequences of early Aquitanian, late Aquitanian, and early Burdigalian age based on the main features of microfaces, their depositional environments, and shallowing and deepening-upward trends. Microfacies of the Transgressive System Tract (TST) have been affected by compaction, dissolution (moldic), cementation, and slightly dolomitization in the middle to outer ramp parts. The Highstand System Tract in the inner ramp part has been affected by dolomitization, dissolution, and fracturing close to the sequence boundaries, and has a better reservoir quality than the Transgressive System Tract. Manuscript profile