List of articles (by subject) Petroleum Geology
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Open Access Article
1 - FXGHFGH
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Open Access Article
2 - Biostratigraphy and sequence stratigraphy of the Sarvak Formation at Fahliyan Anticline (South of Yasuj)
In this study, biostratigraphy, depositional environment and sequence stratigraphy of the Sarvak Formation at Fahliyan Anticline was studied. 8 species of benthic foraminifera (4 genera) and 8 species of planktonic foraminifera (11 genera) in the study area were recogn MoreIn this study, biostratigraphy, depositional environment and sequence stratigraphy of the Sarvak Formation at Fahliyan Anticline was studied. 8 species of benthic foraminifera (4 genera) and 8 species of planktonic foraminifera (11 genera) in the study area were recognized. 6 biozones have been recognized by distribution of the foraminifera, which in stratigraphic order are: Favusella washitensis Zone, Orbitolina-Alveolinids Assemblage Zone, Rudist debris Zone, Oligostegina flood Zone, Whiteinella archaeocretacea Zone and Helvetoglobotruncana helvetica Zone. On the basis of these, the age of Albian–Turonian was considered for the Sarvak Formation. Based on petrography and analysis of microfacies features 9 different microfacies types have been recognized, which can be grouped into 3 depositional environments: lagoon, shoal and open marine. The Sarvak Formation represents sedimentation on a carbonate ramp. Sequence stratigraphy analysis led to identification of 4 third-order sequences. Manuscript profile -
Open Access Article
3 - Studying Maturity and Migration Routes Using Two-Dimensional Modeling in a number of Dezful Dam Oilfields
Ashkan Maleki Seyed Ali Moallemi Mohammad Hossein Saberi Mohammad Hassan JazayeriTo the southwest of Iran there are large reservoirs of oil and gas including Jurassic and Cretaceous carbonates, with good source rocks in the succession of the Early Cretaceous and Jurassic. The purpose of this study was to investigate the production, migration and cha MoreTo the southwest of Iran there are large reservoirs of oil and gas including Jurassic and Cretaceous carbonates, with good source rocks in the succession of the Early Cretaceous and Jurassic. The purpose of this study was to investigate the production, migration and characterization of Pabdeh, Kazhdumi, Garru and Serglu source rocks in the study area. For this purpose, burial history and one-dimensional thermal modeling in four wells and two-dimensional modeling in one section for the study area were evaluated using Openuploo software to determine the maturity of layers and hydrocarbon outflow. Comparison of measured vitrinite temperature and reflectance values with model results was used for model calibration. The results of one-dimensional modelling of the burial and thermal history in this study show that the Sergloo, Grove and Kazhdumi formations have reached maturity and have had hydrocarbon outflow, but the Pabdeh Formation has not reached sufficient maturity for hydrocarbon maturation and production. The results of migration model in the studied section show that the two Early Cretaceous and Middle Cretaceous hydrocarbon systems were separated by Kazhdumi Formation and therefore hydrocarbon migration in deeper layers of Kazhdumi was mostly lateral to Abadan plain. The hydrocarbon produced from the Kazhdumi Formation, in addition to ornithologically rearing the upper layers, migrated to the Ilam and Sarvak layers due to the general slope of the layers laterally and toward the Abadan plain. In general, the process of maturation of source rocks decreased from east to west of the study area. Manuscript profile -
Open Access Article
4 - Drilling mud loss modeling to detect high risk point and suitable location for new drilling project in Sarvak Formation, Azadegan Oil Field
Bahman Soleimani Abass Esmaeli Ehsan LarkiDrilling mud loss is considered as one of common problems encountered during excavation. The aim of this study is to evaluate of mud loss of the Sarvak Formation (Cenomanian age) in Azadegan oil field which is known as the most important rich hydrocarbon reservoir in th MoreDrilling mud loss is considered as one of common problems encountered during excavation. The aim of this study is to evaluate of mud loss of the Sarvak Formation (Cenomanian age) in Azadegan oil field which is known as the most important rich hydrocarbon reservoir in the Zagros region by providing the model in the environment of GS+ software. This formation consists of a thick sequence of limestone and clay limestone layers, which is divided into 7 zones based on petrophysical characteristics. For this purpose, available data such as drilling mud weight, pump pressure, mud loss, and related depths of 9 drilled wells were investigated. The results showed that despite of the operating factors including the weight of drilling mud and the pressure of the pumps were kept constant, the presence of fractures in the reservoir rocks causes to occur mud loss significantly in zone 3 while it is observed the lowest level of mud loss in zone7. Based on the results of mud lost data patterns, faults, sedimentary environments morphology (such as sedimentary channels) seem to play major roles in creating fractures or areas susceptible to mud loss. The difference in observed patterns of mud loss is more likely to confirm the relocation of channel status over the time in different parts of the reservoir. In general, the highest rate of mud loss was detected in the northern and southern edges while the lowest rate was happened in the middle part of the field. It is suggested to prevent mud loss hazards in this field, underbalanced drilling method should be used. Manuscript profile -
Open Access Article
5 - Biostratigraphy, conodont biofacies and CAI of Late Devonian-Carboniferous deposits in Anarak section, Central Iran
ٍٍElahe Sattari Ali Bahrami Hosyen Vaziri moghadam Ali Taheri Sandra Isabella Kaiser Peter KönigshofStudy of Late Devonian-Carboniferous (Mississippian-Pennsylvanian) conodonts Anarak section (NE Isfahan), Central Iran, led to identifying 67 conodont species belonging to 18 genera. 22 conodont bio-intervals were separated; 15 biozones belong to Late Devonian and 7 b MoreStudy of Late Devonian-Carboniferous (Mississippian-Pennsylvanian) conodonts Anarak section (NE Isfahan), Central Iran, led to identifying 67 conodont species belonging to 18 genera. 22 conodont bio-intervals were separated; 15 biozones belong to Late Devonian and 7 biozones belong to carboniferous (Mississippian-Pennsylvanian) time interval. Based on field observation and sedimentological featurs and charactristics the section, subdivided into 5 lithostratigrafic unit. The Color Alteration Index (CAI) reveals the hydrocarbure potential for the Famennian stage of the studied interval Manuscript profile -
Open Access Article
6 - Cyclostratigraphy study of Asmari reservoir in Karanj, Paranj and Parsi oil fields
Ardavan Khalili Hosyen Vaziri moghadam Mehran ArianThe most important reason for studying any oil reservoir is the more efficient use of the production parts of the reservoir and the first step in identifying the reservoir is its zoning. Zoning is determined based on lithological changes by combining production data and MoreThe most important reason for studying any oil reservoir is the more efficient use of the production parts of the reservoir and the first step in identifying the reservoir is its zoning. Zoning is determined based on lithological changes by combining production data and petrophysical logs in each reservoir. In order to improve and accelerate the zoning of oil reservoirs, like other branches of science, the use of software has become common in recent years. One of the most powerful of these software's is Cyclolog. The science of using this software is cyclostratigraphy, which can be used to separate reservoir zones based on sedimentary cycles and their knowledge. Cyclolog software with the help of petrophysical logs taken from the wellbore and especially gamma diagram (GR) allows subsurface matching and preparation of matching charts in selected wells. In this study, in the three oil fields studied (Karanj, Paranj and Parsi) using cyclolog software, a total of seven positive timelines (Pb3000, Pb2000, Pb1500, Pb1000, Pb500, Pb400, and Pb300) as well as five negative timelines (Nb4000, Nb3000, Nb2000, Nb1000, and Nb500) were detected. Accordingly, the Pb1500 timeline is the separator and the boundary of the Chattian and Aquitanian peaks, which in the wells of all three studied fields almost cross the boundary of reservoir zones 3 and 4. The Nb4000, Nb3000, and Nb2000 timelines are also Chattian age. The Nb3000 timeline in Karanj oil field has crossed the boundaries of zones 4 and 5 in most of the wells due to calibration with biometric evidence (biostratigraphy) and indicates the top of the formation. The age of the Nb500 timeline is Burdigalian and passes through the middle of their reservoir zone 1 in the study area. The boundary between the Aquitanian and Burdigalian peaks is defined by the Nb1000 timeline. This timeline crosses the boundaries of zones 1 and 2 in all three fields studied Manuscript profile -
Open Access Article
7 - Investigating the role of microfacies, depositional conditions and diagenesis on the quality of the reservoir section, Ilam Formation (Santonian-Campanian) in one of the fields in southwestern Iran, Dezful embayment
Seyedeh Akram Jooybari Peyman Rezaei Majid MehdipourThe 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 on MoreThe 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. Manuscript profile -
Open Access Article
8 - Microfacies and Sequence stratigraphy of the the Qom Formation in Kuh-e Charkheh (Natanz), Western Zefreh and Varton sections, northeastern Isfahan
Amir Pedramara Mehdi Yazdi Zahra Maleki Ali BahramiIn 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 sect MoreIn 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. Manuscript profile -
Open Access Article
9 - Investigating the reservoir quality of Sarvk formation using multi-resolution graph-based and comparing it with petrographic data in an oilfield of Dezful Embayment
Seyedeh Akram Jooybari Payman Rezaee Majid MehdipourSarvak 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. T MoreSarvak 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. Manuscript profile -
Open Access Article
10 - Reconstruction of Asmari Formation Sedimentary Environment in Asmari and Gurpi Anticlines in the oil field of Masjed Soleiman (Southwest of Iran)
Navab Varnaseri Davood Jahani Nader Kohansal Ghadimvand Mohsen PourkermaniIn this research, the process of lithological changes and diagenetic processes of Asmari formation with Oligo-Miocene age has been investigated. For this purpose, 400 samples were selected and collected from a section of the Masjid Suleiman oil field and the surface sec MoreIn this research, the process of lithological changes and diagenetic processes of Asmari formation with Oligo-Miocene age has been investigated. For this purpose, 400 samples were selected and collected from a section of the Masjid Suleiman oil field and the surface section of the Asmari anticline in the Dezful depression and the Gurpi anticline in the Izeh zone. Petrographic studies revealed 18 sedimentary microfacies that were deposited on a ramp-type carbonate platform. Among the significant diagenetic processes in the region are the process of micritization, bioturbation and the influence of burrowing organisms, cementation (types of cement related to marine, meteoric and burial diagenesis environments), dissolution (meteoric and burial dissolution), dolomitization (in different phases), silicification, pyritization, phosphatization, mechanical compaction, chemical compaction, fracture and porosity. Based on the identification of the sequence boundaries and following the facies depth changes, the carbonate sequence of the Asmari formation in the subsurface section and the Asmari anticline section are introduced in the form of 3 sedimentary sequences of the third order shallowing upwards, which are the former Aquitanian, the late Aquitanian and Bordigalin belong. Among the dominant porosities in the Asmari Formation, we can mention the hole, mold and fracture porosities. Manuscript profile -
Open Access Article
11 - Examination of climatic orbital changes and sedimentation rate in the Ilam Formation in the Kupal oilfield, Dezful Embayment
Forough Abasaghi Armin OmidpourCarbonate 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 MoreCarbonate 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. Manuscript profile -
Open Access Article
12 - Reservoir characteristics prediction using the geostatistical model. Case study: Bangestan reservoir, Ziloi Field, SW Iran
Somaieh Khoram abadi Bahman Soleimani Hussin SheikhzadehThe geostatistical model is considered as a useful tool for predicting the oil potential of reservoirs. In the present study, an attempt is made to review the importance of the geostatistical model in the reservoir characteristics, to model and examine the changes in th MoreThe geostatistical model is considered as a useful tool for predicting the oil potential of reservoirs. In the present study, an attempt is made to review the importance of the geostatistical model in the reservoir characteristics, to model and examine the changes in the petrophysical parameters of the Bangestan reservoir in the Ziloi field despite the limited number of boreholes. This carbonate reservoir consists of Ilam, Surgah and Sarvak formations and was divided into eight zones. In the modeling process, the information required for the 3D model, including geophysical interpretations, well description information, and 2D maps along with their quality control (QC), were entered into the RMS software. The construction model was prepared based on the top levels of the structures and the depth information of the wells entering the reservoir. These data were used indirectly or directly in software with high grading capability to create levels. The depth level map of the top of Ilam Formation was entered into the model as an interpretation level, digitalization and as a base contour map. Isochore maps of other zones were prepared using the depths of wells entering different parts of the reservoir. The prediction of the distribution pattern of changes in the petrophysical features of the reservoir was prepared based on geostatistical methods, average porosity maps, and water saturation. According to the results of the modeling, it was revealed that the Ziloi field has a structural complexity, caused the heterogeneity of the reservoir and increased the risk of predicting the behavior of the reservoir. Comparison of reservoir zones showed that zone 3 has better hydrocarbon potential than other zones. One of the effective factors to improve its reservoir quality is the dolomitization process. Changes in the distribution values of water saturation and porosity showed that the reservoir properties improve from the southeast to the northwest of the field. Manuscript profile -
Open Access Article
13 - Depositional Environmental Analysis of Shally Units of Pabdeh-Gurpi Formation and Clay Minerals Effect on Wellbore Stability, Aghajari Oil Field
بهمن سلیمانی Zahra DehghaniShally units are one of the most problematic parameters in the process of drilling oil reservoirs. The current study is related to the instability of the wellbore due to the presence of clay minerals bearing shally units of the Pabdeh-Gurpi formations in Aghajari oilfie MoreShally units are one of the most problematic parameters in the process of drilling oil reservoirs. The current study is related to the instability of the wellbore due to the presence of clay minerals bearing shally units of the Pabdeh-Gurpi formations in Aghajari oilfield. Investigation and identification of shales were done using the XRF laboratory and NGS logs. The results showed that the NGS method is sensitive and applicable to identify Illite mineral merely. According to Fe2O3 content, the upper part of the oxidant conditions, but towards the Gurpi, is dominated by reduction condition. The role of other elements in the formation of clay minerals was discussed. Based on the amount of iron, manganese and vanadium, the samples are classified as the Quinby_Hunt and Wilde class lll (non-sulfide resuscitation but Eh recovery and medium to low pH). The range of changes in the Th/U ratio (4-1.5) signified an environment with changes from sea to intermediate states. Manuscript profile