فهرست مطالب سیده اکرم جویباری

The Bakhtiari Formation represents the Middle Pliocene-Pleistocene time period in the folded Zagros structural sedimentary zone. Debris deposits of this formation have wide outcrops in the northern area of Bandar Abbas city. In order to study the Bakhtiari formation from the point of view of sedimentary geology, three sections of this formation were selected in the northwest of Bandar Abbas city (Genow Power Plant, South of town Down Tazeyan, South of town Morvarid). From these sections, 50 samples were taken for microscopic examination and 6 samples were taken to identify heavy minerals. In all three sections, the Bakhtiari Formation includes an interval of conglomerate, sandstone and some mudstones. In the studied area, this formation is placed on the Aghajari formation with an erosional discontinuity boundary. The upper border of the Bakhtiari Formation with Quaternary deposits is also of erosional discontinuity. Field and laboratory investigations led to the identification of coarse-grained petrofacies (mud-supported conglomerate and grain-supported), medium-grained (calclitite sandstone), fine-grained (mudstone) and five structural elements (GB, CH, SB, GH, FF) has been. The results of this research show that the deposits of the Bakhtiari Formation in the north west of Bandar Abbas has been deposit in a braided river far from origin at the end of an alluvial fan. The set of heavy minerals identified in this sequence have two origins, Hormuz Salt Series and Sanandaj-Sirjan Zone, which have been affected by several sedimentary cycles. The set of petrofacies features of the Bakhtiari Formation is a confirmation of the tectonic dynamics of the end of the Cenozoic era in the middle Pliocene-Pleistocene time frame, especially the Bakhtyari tectonic event, which has led to the intensification of continental conditions in the studied area.

In this research, the effect of monsoon phenomenon on the textural characteristics of the sediments of Iranian coasts of the Oman Sea was investigated. For this purpose, necessary sampling was done from 13 stations based on marine sedimentological standards. According to the amounts of sand, silt and clay in the pre-monsoon and post-monsoon samples, the sedimentary types of sand, clayey sand, sandy clay and clay were identified in the studied stations. Granulometric analysis showed that the amount of sand and clay in pre-monsoon samples of shallow and near-shore stations (Tiss, Desalination, Center of the Bay, Ramin, Beris and Pasabandar) range from 43 to 97 and 0 – 27%, respectively. On the other hand, these values change between 8 – 45% and 54 - 82 % in deep and offshore stations, respectively. The amount of sand and clay in post-monsoon samples of shallow and near-shore stations vary between 68% - 96% and 0% - 13%, respectively. The amount of sand and clay in deep stations and far from the coast in post-monsoon samples fluctuates between 8-22% and 58-86%. The amount of organic matter in sediments varies between 1 and 3% in most of the studied stations and is within the normal range. This amount showed a slight increase in Konarak and Ramin stations due to human pollutants and fine-grained sedimentary texture. The low amount of organic matter in the desalination station can be caused by the inflow of more saline wastewater into the bay environment

Asmari Formation (Rupelian-Burdigalian) is one of the most well-known formations in Iran. In order to investigate the stratigraphy and sedimentary environment, a section of this formation was selected in Khamir salt mountain section in Bandarlengeh embayment. In this number, 70 limestone microscopic thin sections and 3 marl samples (XRF) were evaluated to identify the microfacies and the sedimentation conditions.The petrographic study led to the identification of 10 microfacies belonging to the facies belts of tidal, lagoon, carbonate bar, open marine, which were deposited in the homoclinal carbonate ramp environment. The composition of marl facies oxides also indicates the presence of carbonate minerals, quartz and clay minerals, which along with field observations and alternating calcareous facies suggest that this facies was deposited in an open marine environment. Finally, it seems that the facies and fossil diversity of the Asmari Formation in the mentioned section is such that during the Aquitanian stage, this formation was located closer to the coast line and during the Rupelian and Chattian-Burdigalian times, it was located at a further distance from the coast line.

Sarvak Formation is one of the important carbonate reservoirs in Dezful Embayment. In order to evaluate the reservoir quality of this formation in one of the Dezful Embayment fields, multi-resolution graph-based method was used and compared with petrographic findings. The findings showed that the Sarvak formation in the studied field consists of 8 microfacies belonging to the sub-environments of the lagoon, carbonate bar, middle ramp and outer ramp, which were deposited in a homoclinal ramp environment. The main diagenesis processes affecting this reservoir include cementation, dissolution, fracture, stylolitization, and dolomitization. The results of multi-resolution graph-based analysis led to the identification of 3 electrofacies, EF1 electrofacies had the weakest reservoir parameters and EF3 facies had the best reservoir status. The majority of EF1 microfacies are grainstone microfacies and the majority of EF3 microfacies correspond to wackstone and packstone microfacies. Based on this, it seems that the lagoon sub-environment has a better reservoir condition than other sub-environments, especially the carbonate bar, and this is an important sign of the different performance of diagenesis processes in these sub-environments. In a vertical trend, the highest volume of hydrocarbon column is in the EF3 electrofacies and the lowest is EF1. In general, it can be stated that the use of multi-resolution graph-based analysis and comparison with petrographic findings is a suitable solution for accurate evaluation of the reservoir quality of carbonate reservoirs.

The Ilam formation is one of the important carbonate oil reservoirs of the Zagros and Dezful embayment basins. In order to identify the microfacies and depositional conditions and diagenesis processes, 100 microscopic thin sections from one well of this reservoir in one of the Dezful embayment oil fields were evaluated. Porosity and permeability data were used to check reservoir quality. The petrographic study led to the identification of 9 microfacies belonging to the facies belts of lagoon, barier, middle ramp and outer ramp, which were deposited in the homoclinal ramp environment. The most important diagenesis processes identified in Ilam reservoir include cementation, dissolution, fracture, micriteization, stylolitization, and dolomitization. Based on the qualitative classification of the reservoir and Lucia's petrophysical diagrams, the lagoon facies and the middle ramp have an average reservoir status, and the carbonate barier facies and the outer ramp have a weak reservoir status. The reservoir quality of the lagoon and middle ramp facies is related to the existence of interconnected and channel porosities. Due to strong cementation and the presence of unrelated porosity such as mold porosity, the carbonate barier facies has low permeability and has a poor reservoir status. In general, the Ilam Formation in the studied field is in a weak state in terms of reservoir, which can be important in addition to the facies controllers in relation to the lack of expansion of fracture and dolomitization and the excessive expansion of cementation in these facies. Therefore, the Ilam Formation in the studied field has a weak reservoir performance due to diagenetic processes, despite having more shallow sequences than deep ones.

Sarvak Formation is one of the important oil reservoirs in the Zagros Basin. In this study, 150 thin sections were evaluated to identify microfacies and sedimentation conditions and diagenetic processes. Porosity and permeability data were used to determine the flow units and to analyze the Reservoir quality by Lucia petrophysical method. Petrographic study led to the identification of 10 microfacies belonging to lagoon facies belts, Barier , middle ramps and outer ramps that were deposited in the environment of homoclinal carbonate ramps. The most important diagenetic processes identified in the Sarvak reservoir include cementation, dissolution, dolomitization, fracture and stylolitization. Analysis of porosity-permeability data using FZI index also led to the identification of 3 hydraulic units. The HFU1 unit with the weakest reservoir status is mainly characterized by lagoon microfacies and outer ramps, and the HFU2 and HFU3 reservoir units have a better reservoir status and mainly have lagoon facies belt, carbonate bar and middle ramps. Porosity, permeability, reservoir quality index, flow zone index and reservoir potential showed that the reservoir status of Sarvak Formation in the study area is in good to very good class. It can also be said that for each facies belt, lagoon facies and carbonate bar have better reservoir indices. The different reservoir status of the facies belts of Sarvak Formation shows the combined performance of sedimentary and diagenetic processes and has a complex effect on the reservoir sequence and its reservoir parameters in Southwest of Iran.

Hendijan wind erosion center is located in Khuzestan Province and southwest of Iran. In the last decade, with the increase of erosion rate and concentration of important dust centers in this area, the study of heavy metal concentration and pollution in this area has become very important. For this purpose, 33 soil samples of this zone were collected based on land use change and with the aim of uniform distribution and analyzed by ICP-MSS. The obtained data show that the highest average concentrations of metals belong to Cd <As <Cu <Pb <Zn <Ni <Cr, respectively. Enrichment indices, geo-accumulation index and contaminant factor showed that the highest pollution in Hindijan area belongs to nickel, chromium, arsenic, cadmium and plumbum, respectively. On the other hand, ecological risk assessment in the mentioned area has shown that this region has a low ecological risk that among the studied metals, the highest ecological risk belongs to the two metals arsenic and cadmium. The results of PCA test showed that the metals nickel, zinc, copper and lead have both non-anthropogenic and anthropogenic sources and the source of arsenic and cadmium metals is human activities. According to the pattern of metal distribution, it can be stated that the activities related to Bahrkan fishing pier on the one hand and oil rigs off the coast of Hindijan oil field on the other hand have caused the concentration of nickel, lead, zinc and copper in the south of the study area. Agricultural activities have also controlled the concentration of cadmium and arsenic metals in this area, and the source of chromium concentration was determined as agricultural effluents, traffic pollution and residual pollution from the 8-year Iraq-Iran war.

The phenomenon of fine dust is one of the most important environmental challenges nowadays. Recognition of this phenomenon and strategies in dealing with it is one of the new topics in environmental sedimentology. Detection of dust centers is possible by using various methods such as telemetry and satellite techniques, sedimentology and geochemistry studies, sediment tracking with the help of statistical models and data mining or a combination of these methods. The most important causes of dust are drought, erosion, lack of vegetation and improper management of water resources. To deal with the effects of dust, mulching, construction of windbreaks, construction of sediment traps and proper management of water resources are the most important factors and strategies to reduce dust storms and stabilize dust hotspots. The dust phenomenon has had a direct impact on human health and the agricultural and construction sectors, and imposed a direct and indirect impact on the economy and reduced quality of life. Existence of seven internal dust centers along with about 5 external dust centers in Khuzestan province has caused this province to be constantly exposed to dust storms. The sedimentological composition of these fine dusts generally falls into three groups: silicate, carbonate and evaporation, and the main sedimentary type of deposits in the interior of Khuzestan plain is sandy mud with a little gravel. Sedimentological parameters of deposits of dust centers of Khuzestan Plain improve in a vertical trend from north to south. The main sources of deposits of internal foci are salt domes, marl formations, sandstone and conglomerate. Environmental monitoring on dust centers and fine dust samples in Khuzestan Plain indicates the existence of environmental pollution affected by the imposed war, oil and petrochemical activities along with industrial and agricultural activities.