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      • Open Access Article

        1 - Porosity modeling in Azadegan oil field: a comparative study of Bayesian theory of data fusion, multi layer neural network, and multiple linear regression techniques
        عطیه  مظاهری طرئی حسین معماریان بهزاد تخم چی بهزاد مشیری
        Porosity parameter is an important reservoir property that can be obtained by studying the well core. However, all wells in a field do not have a core. Additionally, in some wells such as horizontal wells, measuring the well core is practically impossible. However, for More
        Porosity parameter is an important reservoir property that can be obtained by studying the well core. However, all wells in a field do not have a core. Additionally, in some wells such as horizontal wells, measuring the well core is practically impossible. However, for almost all wells, log data is available. Usually these logs are used to estimate porosity. The porosity value obtained from this method is influenced by factors such as temperature, pressure, fluid type, and amount of hydrocarbons in shale formations. Thus it is slightly different from the exact value of porosity. Thus, estimates are prone to error and uncertainty. One of the best and yet most practical ways to reduce the amount of uncertainty in measurement is using various sources and data fusion techniques. The main benefit of these techniques is that they increase confidence and reduce risk and error in decision making. In this paper, in order to determine porosity values, data from four wells located in Azadegan oil field are used. First, multilayer neural network and multiple linear regressions are used to estimate the values and then the results of these techniques are compared with a data fusion method (Bayesian theory). To check if it would be possible to generalize these three methods on other data, the porosity parameter of another independent well in this field is also estimated by using these techniques. Number of input variables to estimate porosity in both the neural network and the multiple linear regressions methods is 7, and in the data fusion technique, a maximum of 7 input variables is used. Finally, by comparing the results of the three methods, it is concluded that the data fusion technique (Bayesian theory) is a considerably more accurate technique than multilayer neural network, and multiple linear regression, when it comes to porosity value estimation; Such that the results are correlated with the ground truth greater than 90%. Manuscript profile
      • Open Access Article

        2 - Porosity estimation with data fusion approach (Bayesian theory) in wells of Azadegan oil field, Iran
        رویا خضرلو هادی کرمانشاهی
        Porosity is one of the main variables in evaluating the characteristics of an oil field. Petrophysical data are normally used to determine these variables. Measurements obtained from well logs, containes some errors and uncertainty. This porosity is influenced by dif More
        Porosity is one of the main variables in evaluating the characteristics of an oil field. Petrophysical data are normally used to determine these variables. Measurements obtained from well logs, containes some errors and uncertainty. This porosity is influenced by different factors, such as temperature, pressure, fluid type, clay content and the and amount of hydrocarbons. One of the best, and yet most practical ways to reduce the amount of uncertainty in porosity measurement is using various sources of data and data fusion techniques. Data fusion increase certainty and confidence and reduce risk and error in decision making. In this research, the porosity is estimated in 4 wells of Azadegan oil field, with data fusion method (Bayesian theory). To check the ability of generalization of the method, the porosity was also estimated in one other well of this field. A maximum of 7 input variables were used to estimate porosity in this new approach. The results showed that data fusion technique is more powerfull than traditional tecniques for porosity estimation. According to the results, this method has higher credibility than traditional techniques that show 0.7 to 0.8 regressions with log data but data fusion technique showed solidarity over 0.9 with log data. Manuscript profile
      • Open Access Article

        3 - Porosity estimation with data fusion approach (Bayesian theory) in wells of Azadegan oil field, Iran
        عطیه  مظاهری طرئی Hoseyn Memarian Behzad Tokhmchi Behzad Moshiri
        Porosity is one of the main variables in evaluating the characteristics of an oil field. Petrophysical data are normally used to determine these variables. Measurements obtained from well logs, containes some errors and uncertainty. This porosity is influenced by differ More
        Porosity is one of the main variables in evaluating the characteristics of an oil field. Petrophysical data are normally used to determine these variables. Measurements obtained from well logs, containes some errors and uncertainty. This porosity is influenced by different factors, such as temperature, pressure, fluid type, clay content and the and amount of hydrocarbons. One of the best, and yet most practical ways to reduce the amount of uncertainty in porosity measurement is using various sources of data and data fusion techniques. Data fusion increase certainty and confidence and reduce risk and error in decision making. In this research, the porosity is estimated in 4 wells of Azadegan oil field, with data fusion method (Bayesian theory). To check the ability of generalization of the method, the porosity was also estimated in one other well of this field. A maximum of 7 input variables were used to estimate porosity in this new approach. The results showed that data fusion technique is more powerfull than traditional tecniques for porosity estimation. According to the results, this method has higher credibility than traditional techniques that show 0.7 to 0.8 regressions with log data but data fusion technique showed solidarity over 0.9 with log data. Manuscript profile
      • Open Access Article

        4 - Three-dimensional geological modeling in two zones of eastern side of Ahvaz oil field
        Razeyeh . Doosti Irani Maryam Payrovi Mohammad .rahim karimi Mehdi . Doosti Irani
        The Ahvaz field is one of the most important oil fields in the Zagros Basin which is located in the Dezful Embayment. The trend of Ahvaz oil field is northwest- southeast parallel to the Zagros mountains. The purpose of this study is the geological 3D simulation (petrop More
        The Ahvaz field is one of the most important oil fields in the Zagros Basin which is located in the Dezful Embayment. The trend of Ahvaz oil field is northwest- southeast parallel to the Zagros mountains. The purpose of this study is the geological 3D simulation (petrophysical) for the zone one and two in the eastern part of the Ahvaz oil field. In this investigation, porosity modeling, water saturation and shale volume by using sequential Gaussian Simulation (SGS) was performed. At first, well logs, cores, well’s coordination, top and thickness of formations of the zone three of Ilam Formation and zone one of Sarvak Formation were collected. These information related to 25 wells in the eastern part of the Ahvaz oil field was used for the 3D modeling of the reservoir by using Petrel software. For the recognition of spatial correlation, variograms based on water saturation and permeability and three dimensional model of the petrophysical parameters and net to gross ratio (NTG) were drawn. Manuscript profile
      • Open Access Article

        5 - Electro-facies analysis of the Sarvak Formation (Middle Cretaceous) and compliance with sedimentary microfacies in an oil field, SW Iran.
        zahra Eghbalkiani Taher Goli ALI HOSSEIN JALILIAN Rahym Kadghodaii
        Electro-facies analysis is a sure method in clustering petrophysical logs analysis that can well indicates the changes of geologic charactereristics of the different lithostratigraphic units as well. Petrographic studies of 120 prepared thin sections of the upper parts More
        Electro-facies analysis is a sure method in clustering petrophysical logs analysis that can well indicates the changes of geologic charactereristics of the different lithostratigraphic units as well. Petrographic studies of 120 prepared thin sections of the upper parts of the Sarvak Formation in studied oilfield, Southwestern Iran, has resulted in definition of 6 microfacies sedimentary types. These data suggested that the middle Creataceous sediments in the studied area were predominantly deposited in two subenviornments of patch organic barrier and lagoon corresponding to inner and shallow a homoclinal ramp. In addition, using petrophysical logs in the studied well, 10 electrical facies were determined. By analyzing the data petrophysical in Geolog software, 10 electerical facies were optimized and then their number was reduced to six. According to good adaptation of optimized electerical facies with sedimentary microfacies, we would generalized obtained dresults to all parts of the Sarvak Formation. Study of porosity changes in the electrical diagrams such as CGR corrected Gamma, and sonic curves in mentioned well, indicated a significant reduction in facies porosity of 1 to 6. In addition, the results showed that the reservoir quality reductionin studied microfacies is corresponded to Bioclastic Rudist debris floatstone/ Rudstone, Benthic foraminifera Rudist debris wackestone / packstone, Benthic Foraminifera peloid Grainstone/Packstone, with High diversity benthic foraminifera wackestone / packstone, Peloid bioclastic wackestone /packstone with Low diversity benthic Foraminifera and Mudestone/Wackestone, respectively. In this study, we concluded that comparison and correlation sedimentary facies with electric microfacies provide an efficient method to study the quality of the hydrocarbon reservoir system that especially can be used in other wells with no core. Manuscript profile
      • Open Access Article

        6 - 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 Larki
        Drilling 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 More
        Drilling 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

        7 - Interpretation of sedimentary environment and factors affecting reservoir quality in upper Sarvak Formation in one the oil fields of Abadan plain
        Mohammad Hossein Saberi Bahman Zarenezhad الهام  اسدی Nasim Rahmani
        The Sarvak Formation of the Albian-Turonian Formation is one of the most important hydrocarbon reservoirs in south and southwest of Iran. In this study, in order to assess the reservoir quality, from a petrographic study and porosity and permeability data, an important More
        The Sarvak Formation of the Albian-Turonian Formation is one of the most important hydrocarbon reservoirs in south and southwest of Iran. In this study, in order to assess the reservoir quality, from a petrographic study and porosity and permeability data, an important well in one of the oil fields of Abadan plain has been used. Based on microscopic studies, 13 microfacies have been identified in the form of Four facies tidal flat, lagoon, shoal and open marine for Sarvak Formation deposits in the studied oil field, indicating that the upper part of the Sarvak Formation is deposited in a homoclinal carbonate ramp. Among the identified diagenetic processes, dissolution, cementation, dolomitization, fracturing, compaction, neomorphism, micritization, bioturbation, pyritization, hematitization, phosphatization and silicification are mentioned. Diagenetic processes of Sarvak Formation occurred in three marine, meteoric and burial environments. Among the dissolution and fracturing diagenetic processes, the most important role has been in increasing the reservoir quality, and cementation and compaction have been the most important factors in reducing reservoir quality. Sequence stratigraphy studies identified third order sedimentary sequences of the age of Turonian, Late Cenomanian, and Middle Cenomanian, and studied the facies and diagenetic processes within its framework. Correlation of porosity and permeability data of the core showed that the reservoir quality in this formation was influenced by facies and diagenetic processes. So that the microfacies containing the rudist have the highest reservoir quality. Due to the diagenetic processes, sedimentary and porosity and permeability data, the facies shoal and open marine to the land have the best reservoir quality. Manuscript profile
      • Open Access Article

        8 - Interpretation of sedimentary environment and factors affecting reservoir quality in upper Sarvak Formation in one the oil fields of Abadan plain
        Arad Kiani Mohammad Hossein Saberi Bahman Zare nejad Elham Asadi Nasim Rahmani
        The Sarvak Formation of the Albian-Turonian Formation is one of the most important hydrocarbon reservoirs in south and southwest of Iran. In this study, in order to assess the reservoir quality, from a petrographic study and porosity and permeability data, an importan More
        The Sarvak Formation of the Albian-Turonian Formation is one of the most important hydrocarbon reservoirs in south and southwest of Iran. In this study, in order to assess the reservoir quality, from a petrographic study and porosity and permeability data, an important well in one of the oil fields of Abadan plain has been used. Based on microscopic studies, 13 microfacies have been identified in the form of Four facies tidal flat, lagoon, shoal and open marine for Sarvak Formation deposits in the studied oil field, indicating that the upper part of the Sarvak Formation is deposited in a homoclinal carbonate ramp. Among the identified diagenetic processes, dissolution, cementation, dolomitization, fracturing, compaction, neomorphism, micritization, bioturbation, pyritization, hematitization, phosphatization and silicification are mentioned. Diagenetic processes of Sarvak Formation occurred in three marine, meteoric and burial environments. Among the dissolution and fracturing diagenetic processes, the most important role has been in increasing the reservoir quality, and cementation and compaction have been the most important factors in reducing reservoir quality. Sequence stratigraphy studies identified third order sedimentary sequences of the age of Turonian, Late Cenomanian, and Middle Cenomanian, and studied the facies and diagenetic processes within its framework. Correlation of porosity and permeability data of the core showed that the reservoir quality in this formation was influenced by facies and diagenetic processes. So that the microfacies containing the rudist have the highest reservoir quality. Due to the diagenetic processes, sedimentary and porosity and permeability data, the facies shoal and open marine to the land have the best reservoir quality. Manuscript profile
      • Open Access Article

        9 - Hydrodynamic activity in the Mishrif reservoirs: an approach to characterize Sarvak formation , in eastern part of the Persian Gulf
        Ali reza Bashari
        The hydrodynamic activity and its effects on oil water contact of oil fields in Sirri district ( Eastern Part of the Persian Gulf), has been revealed by drilling and coring of third well of Mishrif reservoir, (SiDA1) on 1976. Discovery of Sirri –D1 ( Dena) i More
        The hydrodynamic activity and its effects on oil water contact of oil fields in Sirri district ( Eastern Part of the Persian Gulf), has been revealed by drilling and coring of third well of Mishrif reservoir, (SiDA1) on 1976. Discovery of Sirri –D1 ( Dena) in 1972 and SiD-2 confirm existence of oil only 5 meter at the top of structure. Field development started in 1975 and showed the existence of tilted, oil- water contact along fairly south –north direction with slopes up to 12:1000, particulary on the western flank of structure. Slope and direction of water level of Sirri-C ( Sivand) which is close to Sirri-D (Dena) , contain the same slope in both field, at the eastern border of field. The oil –water contact of Sirr- E, (Alvand) field has been constructed with good accuracy and fair probability in 1978. As a result, this modeling was confirm with actual result after full field development of this field on 2002. An entirely original study has been undertaken on residual oil of core, which permitted to characterize various zone as well as modern and fossil interfaces, and proved Hydrodynamic activity in the Mishrif reservoir in western part of Persian Gulf ( Sirri District). This study was carried out, with an approach to combined reservoir characterization , and revealed accuracy of results after full development of these fields. Manuscript profile
      • Open Access Article

        10 - 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 Mehdipour
        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. T More
        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. Manuscript profile
      • Open Access Article

        11 - Petrographical factor and Petrophysical parameter: An approach to reservoir evaluation of the Sarvak formation in NW, of the Persian Gulf
        Alireza Bashari
        Sarvak formation is a major oil reservoir in the Persian Gulf. Various nomenclature of the Sarvak formation were applied by different operative oil companies In the northern part of the Persian Gulf. The aim at this study is to harmonize stratigraphical nomenclatu More
        Sarvak formation is a major oil reservoir in the Persian Gulf. Various nomenclature of the Sarvak formation were applied by different operative oil companies In the northern part of the Persian Gulf. The aim at this study is to harmonize stratigraphical nomenclature in this district , as well as to study the reservoir qualities and to asses hydrocarbon accumulations in this area. By using different petrophysical data and integration with geological factor, resulted in revealing three stratigraphy members ( Mishrif, Ahmadi and Mauddud), as well as reservoir qualities variations , in this district. By applying, available petrophsical data, and integration with geological information, various 3D geological maps, ( porosity, water & oil saturation maps etc…) were made. Preliminary assessment of the reservoir potential of the Bahregansar & Hendijan Fields shows , Sarvak formation in these two fields, have a good reservoir qualities, but other part of this district has poor reservoir qualities. This study shows , having high portions of clay mineral in the Sarvak reservoir along with lack of suitable cap rock and poor reservoir qualities , diminished reservoir potentials in this district. Manuscript profile