Microfacies and Sequence stratigraphy of the the Qom Formation in Kuh-e Charkheh (Natanz), Western Zefreh and Varton sections, northeastern Isfahan

perISPGمجله زمین شناسی نفت ایران 2251-87382251-87382023-111223120articleMicrofacies and Sequence stratigraphy of the the Qom Formation in Kuh-e Charkheh (Natanz), Western Zefreh and Varton sections, northeastern Isfahan Amir Pedramaraa.pedramara@gmail.com1Mehdi Yazdimeh.yazdi@gmail.cim2Zahra Malekizmaleki.iau@gmail.com3Ali Bahramibahrami_geo@yahoo.com4واحد علوم و تحقيقات، دانشگاه آزاد اسلامي، تهران، ايرانProfessor, Stratigraphy and Paleontology, Department of Geology, Faculty of Sciences, University of Isfahan, Isfahan, IranAssistant Professor, Tectonics, Department of Geology, Science and Research branch, Islamic Azad University, Tehran, IranAssociate Professor, Stratigraphy and Paleontology, Department of Geology, Faculty of Sciences, University of Isfahan, Isfhan, IranIn this research, the deposits of the Oligocene-Miocene Qom Formation in Kuh-e Charkheh (Natanz), Western Zefreh and Varton sections, northeastern Isfahan were studied. According to the field observations and thin section analysis in Carbonate part of the mentioned sections, 8 microfacies were identified, which were deposited from shallow part of lagoon to open marine and the sedimentary environment of 3 sections due to absence of reef and presence of bioclastic barrier and absence of spillage, the homoclinal carbonate ramp was detected. According to the sequence stratigraphic studies, each of the studied sections has two 3rd sequences. In Kuh-e Charkheh section, both sequences include of TST and HST, which are separated by sequence boundary SB2. In the western Zefreh section, the first sequence includes of TST and HST that is separated from the second sequence (include of LST, TST and HST) with sequence boundary SB1. In the Varton section, the first sequence is aggredation type and separated from the second sequence, which include TST and HST by a sequence boundary SB2.http://journal.ispg.ir/Article/41326Qom Formation Microfacies Oligocene-Miocene Sequence stratigraphy.perISPGمجله زمین شناسی نفت ایران 2251-87382251-87382023-1112232137articleInvestigating the reservoir quality of Sarvk formation using multi-resolution graph-based and comparing it with petrographic data in an oilfield of Dezful EmbaymentSeyedeh Akram Jooybaris.akramjooybari@gmail.com1Payman RezaeeP.rezaee@hormozgan.ac.ir2Majid Mehdipourm.mehdipoor31@gmail.com3دکتری رسوب شناسی و سنگ شناسی رسوبی دانشگاه هرمزگان، بندرعباس Associate Professor, Department of Geology, University of Hormozgan, Bandar Abbas3- Master of Petroleum Geology, Petroleum Engineering Development Company, TehranSarvak 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.http://journal.ispg.ir/Article/41462Reservoir quality MRGC Sarvak formation PetrographyperISPGمجله زمین شناسی نفت ایران 2251-87382251-87382023-1112233860articleIsotopic and Geochemical comparison of Bangestan and Asmari Oils to determine originationashkan Zardashtiashkanzardashty@gmail.com1Morteza Tabaeimtabaei@iut.ac.ir2mahmood memarianimemarianim@yahoo.com3دانشگاه صنعتی اصفهان Department of Mining Engineering, Isfahan University of Technology Isfahan, Iran of Organic Chemistry, petroleum Industry Research Institute, Tehran, IranIn order to analyze the geochemical characteristics, the oil samples of the Asmari reservoirs and the Bangistan group in the Kopal field were studied using various geochemical techniques such as asphalting technique, gas chromatography technique, gas chromatography-mass spectrometry technique and carbon isotope measurement technique, were subjected to analysis. the purpose of This research is a comparison of carbon isotope and geochemical properties of Asmara and Bangestan oils in Kopal field to determine their parent rock and origin. Considering the results of the testing technique and analysis of biomakers of the esteranes and terpanes family extracted from saturated cutting, it can be stated that the oils accumulated in the Asmari and Bangestan reservoirs of the Kopal field have the characteristics of oil. are paraffinic, which indicates the existence of light oil with good quality, mature, low viscosity and high sulfur. By placing the ratio of biomarker parameters against carbon 13 isotope and examining the general results of the graphs, it was found that the oil samples of Asmari reservoirs and Bangestan reservoirs in the studied field are from a common generative rock. have been found and have the same characteristics and only slightly differ in maturity, degree of fluidity, and the amount of migration processes between the source rock and the reservoir rock, and similarly, the transformation course of the source rock organic materials has occurred naturally in the Copal field. The values of carbon isotopes in the oils indicate the average maturity of the rocks producing the oils. The graph of the ratio of the aromatic carbon 13 isotope against the saturated carbon 13 isotope showed that both field oil samples The subject of study belongs to marine environments.http://journal.ispg.ir/Article/43481Copal field Asmari formation Bangestan formation asphalting carbon 13 isotopeperISPGمجله زمین شناسی نفت ایران 2251-87382251-87382023-1112236188articlePetrophysical Modeling of Lower Zone of Ratawi Formation, using Neural Network Method in Assimilating Seismic and Geological Well Log DataJavid HanachiJavidhanachi@gmail.com1Alireza BashariA_bashari@yahoo.com2 IOOCIranian Society of Petroleum Geology Esfandiar field is located at the northern part of the Persian . This field is a single large anticline with Lulu field of Saudi Arabia, with , 20 KM length and 7 KM width. The field was discovered in 1966 by drilling of well E1, on the northern culmination of the field. wells E3 and E2 were drilled at the top of structure in the southern part of the field. DSTs tests results of E1 proved that the top of Lower Ratawi formation contain 15 m oil column. E3 well test result regards as a dry hole DSTs test results of E2 were not conclusive due to inadequate testing plans . E4 Appraisal well contained, 14 m oil column at the Lower Ratawi. Log interpretations results indicated, E2 and E3 wells contains oil in Yamama formation in the southern part of the field which has not been tested properly. Lower Ratawi (Top oil-bearing zone ), Zone 'B' of Lower Ratawi (Oil bearing zone at bottom), Yamama were constructed based on the existing data. Petrophysical and geophysical data has been used for the Lower Ratawi reservoir, as a result the geological models (structural and porosity models), with applying, related software’s and neural network geophysical method are generated . At the conclusion, the recommended plan consists of horizontal drilling wells for oil production in Lower Ratawi in the north of the field has been proposed. http://journal.ispg.ir/Article/43086Petrophysics Seismic Data Lower Ratawi Fm. Esfandiyar Field Neural Network Persian GulfperISPGمجله زمین شناسی نفت ایران 2251-87382251-87382023-11122389105articleExamination of climatic orbital changes and sedimentation rate in the Ilam Formation in the Kupal oilfield, Dezful EmbaymentForough Abasaghisaghi0631@yahoo.com1Armin Omidpourarmin.omidpour@gmail.com2feddosi National Iranian South Oil Company, Ahvaz, IranCarbonate successions are considered archives for recording the palaeoclimatic proxies and so they are suitable for understanding climatic patterns and identifying the Milankovitch cycles and cycles’s impacts on sea-level changes during Phanerozoic. In the current study, the carbonate successions of the Ilam Formation (Santonian) and their spectral gamma-ray data were chosen to identify the cycles and influencing factors on the sedimentation in one of the oilfields in the Dezful Embayment, southwest of Zagros mountains. According to available evidence, all of Milankovitch cycles contributed to changes in climatic conditions simultaneously with development of the Ilam Formation, however, the long Eccentricity cycles were dominant and have played a greater role in this issue. The sedimentation rate was estimated at 4-5.5 cm/kyr on average in the Ilam Formation. Considering the sedimentation rate and number of identified long Eccentricity cycles, it could be said the deposition in the Ilam Formation lasted in 1.13-1.8 Ma. Our results indicate that the relative sea-level changes in the studied wells correspond to the eustatic sea level. The deposition process in the Ilam Formation was largely affected by the performance of long Eccentricity cycles, eustatic sea level, and tectonic events during the Upper Cretaceous.http://journal.ispg.ir/Article/44329Ilam Formation Zagros Santonian Milankovitch cycles sedimentation rateperISPGمجله زمین شناسی نفت ایران 2251-87382251-87382023-111223106129articleDepositional Environmental Analysis of Shally Units of Pabdeh-Gurpi Formation and Clay Minerals Effect on Wellbore Stability, Aghajari Oil Fieldبهمن سلیمانیsoleimani_b@scu.ac.ir1Zahra DehghaniZahra.dehghani20@gmail.com2Petroleum Geology and Sedimentary basins, Earth Science Faculty, Shahid Chamran University of Ahvaz.Department of Geology, Science and Research branch, Islamic Azad University, Tehran, Iran. Zahra.dehghani20@gmail.com <span style="font-size: 10.0pt; mso-bidi-font-size: 11.0pt; font-family: 'Times New Roman',serif; mso-fareast-font-family: Calibri; mso-bidi-theme-font: major-bidi; mso-bidi-language: FA; mso-bidi-font-weight: bold;">This research is related to detect of clay minerals and geochemical changes of Pabdeh-Gurpi shale formations and their role in borehole instability in Aghajari oil field. For this purpose, these formations were investigated using NGS well log (one well ring), X-ray diffraction method (XRD) and XRF analytical method (11 samples from two wells). In the NGS log, the detected minerals are illite, montmorillonite, mixed layer, glauconite and feldspar. In the XRD method, clay minerals illite, montmorillonite, mixed layer, chlorite and kaolinite were identified in order of abundance.These minerals due to their sensitivity to react with water causes the instability of the borehole. The high ratio of Si/Al and changes of Ti and high level of Fe3+ and Mg are also a sign of the widespread presence of illite, chlorite and montmorillonite in the mentioned formations.   <span style="font-size: 10.0pt; mso-bidi-font-size: 11.0pt; font-family: 'Times New Roman',serif; mso-fareast-font-family: Calibri; mso-bidi-theme-font: major-bidi; mso-bidi-language: FA; mso-bidi-font-weight: bold;">The changes of major and trace elements compared to Al2O3 except for MnO, CaO, and P2O5 showed a positive linear relationship. The changes in the amount of Fe2O3 show the oxidizing conditions in the upper part of the base, but the reducing conditions towards the upper side. Based on the amount of iron, manganese and vanadium, the sediments were formed under conditions of reduction, non-sulphide reduction Eh and medium to low pH. Variations in Th/U ratio (1-4.5) indicate marine to transitional environments. The existence of horizons rich in organic matter (more than 2%) confirms the reduction conditions.   <span style="font-size: 10.0pt; mso-bidi-font-size: 11.0pt; font-family: 'Times New Roman',serif; mso-fareast-font-family: Calibri; mso-bidi-theme-font: major-bidi; mso-bidi-language: FA; mso-bidi-font-weight: bold;">Based on the low values of the Zr/Rb ratio, the sediments in the upper and lower parts are finer than the middle part of the grain. The relative accumulation of biogenic carbonate along with the shale is periodic and is reflected in the changes in the (Zr+Rb)/Sr ratio. Based on the Sr/Ba ratio, marine conditions prevail in the lower part and continental and metamorphic and sometimes marine conditions prevail in the upper part of the formation. Oxidation-reduction conditions were also investigated. The values of the V/(V + Ni) ratio of the semi-reduction region, the Ni/Co ratio of the reduction region and the V/Cr diagram show the almost reduction region and in some cases the oxidant conditions. Paleoclimatic conditions at the time of sedimentation based on low values of Rb/Sr ratio (less than 0.14) were completely hot and dry.  http://journal.ispg.ir/Article/44371Wellbore stability NGS log Pabdeh-Gurpi Formation sedimentary environment Aghajari oilfield.