مخزن

Open Access Article

1 - 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

Open Access Article

2 - Role of the depositional environment and diagenetic effect on reservoir quality of the Upper Surmeh Formation in Salman Field
Ebrahim Sefidari Abdolhossein Amini Mohamad Reza Yousef-Pour Seyed Mohad Zamanzadeh

The Upper Surmeh Formation (Upper Jurassic) consists of limestone, dolomite and interbeded anhydrite equivalent to the Arab Formation in the southern Persian Gulf. This succession is the main producing reservoir of the Jurassic system in the Arabian plate. This research More

The Upper Surmeh Formation (Upper Jurassic) consists of limestone, dolomite and interbeded anhydrite equivalent to the Arab Formation in the southern Persian Gulf. This succession is the main producing reservoir of the Jurassic system in the Arabian plate. This research was carried out based on core (thin section, porosity - permeability, capillary pressure data) and well log data to study the depositional environment and diagenetic effects on reservoir quality of the upper part of the Surmeh Formation. Petrographic investigations led to recognized nine microfacies which were classified in four facies belt including supratidal, intertidal, lagoon and shoal which were deposited in an arid homoclinal carbonate ramp. Diagenetic processes affected reservoir quality of identified microfacies. Among them, dolomitization, anhydritization and cementation are the main effective processes. Dolomitization increased reservoir quality but the anhydritization and cementation decreased reservoir quality. It is important to note that relevant reservoir quality is improved by development of shallow marine facies associations and secondary diagenetic events. Based on the porosity, permeability and mercury injection pressure data, anhydrite and anhydrite bearing mudstone have very low reservoir quality whereas ooid and bioclastic pack ston to grainstone have the best reservoir quality. Manuscript profile

Open Access Article

3 - Reservoir zonation using discrimination of effective and ineffective porosity method in one of the SW Iranian oil Fields; a special look at resistivity logs
جواد هنرمند ژیلا رضائیان دلوئی ارسلان زینل زاده

Abstract In this paper, core samples from Upper carbonates (Miocene age) of the Asmari Formation in one of the SW Iranian oil fields were studied in macro and microscopic scale. Subsequently, results from core and thin section studies compared with core porosity and pe More

Abstract In this paper, core samples from Upper carbonates (Miocene age) of the Asmari Formation in one of the SW Iranian oil fields were studied in macro and microscopic scale. Subsequently, results from core and thin section studies compared with core porosity and permeability and petrophysical wireline logs, especially resistivity logs. Due to texture variation (mudstone to grainstone) and diagenetic events (dolomitization, dissolution, calcite and anhydrite cementation), porosity type and percentage changed in wide range in this formation. This study showed that resistivity logs could be used as an effective tool to distinct effective and ineffective-bearing zones. High permeability intervals have relatively high deep resistivity and high separation between deep and shallow resistivity logs, whereas non-reservoir intervals have low resistivity and very low separation between deep and shallow resistivity. Based on this study, studied carbonate interval of the Asmari Formation was divided into 13 zones. Using separation of deep and shallow resistivity logs, flow zones could be correlated throughout the studied field Manuscript profile

Open Access Article

4 - Reservoir Fluid Contact Detection Using Continues Wavelet Transform of Resistivity Log
امیر ملا جان مصطفی جاوید حسین معماریان بهزاد تخم چی

Exact assessment of reservoir fluid contacts and distribution is an important part of reservoir characterization. Reservoir fluid contacts may be detected by petrophysical interpretations, well testing, special core analysis and seismic inverse modeling techniques. In p More

Exact assessment of reservoir fluid contacts and distribution is an important part of reservoir characterization. Reservoir fluid contacts may be detected by petrophysical interpretations, well testing, special core analysis and seismic inverse modeling techniques. In practice, due to noneconomic and unavailability of well test and seismic data, wire line log data are commonly used. Since these contacts affected by complexity of reservoir properties, thickness of reservoir rocks, and some factors such as vug effect, fractures and mud filtrate invasion, it is essential to find a way for reducing such these factors. The present study uses data related to three wells of an oil field in southwestern Iran to detect oil-water contact by continues wavelet transform of resistivity log. The results obtained from this method are compared with well test responses to validate the proposed algorithm. The results show that this method is capable to detect fluids contact accurately Manuscript profile

Open Access Article

5 - Iagenetic controls on reservoir quality of the Asmari carbonate succession in the Cheshmeh Khush Field, SW Iran
جواد هنرمند عبدالحسین امینی

The Oligo-miocence Asmari Formation in the Cheshmeh Kush Oil Field consists of a mixed carbonate-siliciclastic succession. The carbonate intervals of the Formation display a high degree of vertical heterogeneity created by a complex diagenetic history. This study is aim More

The Oligo-miocence Asmari Formation in the Cheshmeh Kush Oil Field consists of a mixed carbonate-siliciclastic succession. The carbonate intervals of the Formation display a high degree of vertical heterogeneity created by a complex diagenetic history. This study is aimed to investigate the effect of diagenetic events on reservoir quality of carbonate intervals of the Asmari Formation. Core samples and thin sections were studied from sedimentological and diagenetic point of view. Results from cathodoluminesence and scanning electron microscopy were used to investigate diagenetic features in details. Core analysis data (porosity and permeability) and wire-line logs (porosity and oil saturation values) from studied interval were used in order to examine reservoir properties. Diagenetic studies and their comparison with petrophysical data demonstrated that dolomitization, cementation (calcite, anhydrite and celestite cements), compaction and dissolution are the most important diagenetic events affecting porosity and permeability of the reservoir. Based on vertical distribution of diagenetic features and reservoir characteristics, diagenetic zones (DZ) of the carbonate succession were introduced. Medium crystalline dolostones with sparse compaction features and limited anhydrite cement (DZ-23, 27 and 30) comprise the highest value of porosity and permeability. Whereas intense mechanical and chemical compaction and evaporate (anhydrite and celestite) cementation in some dolomitic intervals have thoroughly reduced reservoir quality (DZ-12, 11 and 24). Compaction and calcite cementation (coarse spary, equant and poikilotopic types) in some limestone intervals damaged reservoir properties and created non-reservoir intervals (DZ-3, 20 and 17). In contrast, high value of interparticle and dissolution porosities along with minor compaction and cementation effects has improved reservoir properties of the Asmari limestones (DZ-31 and 32). This study shows that the reservoir characteristics of the Asmari Formation in the studied field are dominantly affected by diagenetic events and therefore diagenetic studies and determination of diagenetic zones in field-scale are the most important part in static reservoir modeling and Manuscript profile

Open Access Article

6 - Reservoir Evaluation of the Kangan Formation based on petrophysical and petrographic studies in one of Persian Gulf fields
سید نظام الدین طبیبی حسین اصیلیان مهابادی بهرام موحد حسن حاجی حسنلو

The Early Triassic Kangan Formation is the main reservoir in the Persian Gulf. In this study reservoir rock types were recognized according to lithology, rock fabric, geometry and amount of porosity. Therefore, 7 reservoir rock types were determined: - Anhydrite without More

The Early Triassic Kangan Formation is the main reservoir in the Persian Gulf. In this study reservoir rock types were recognized according to lithology, rock fabric, geometry and amount of porosity. Therefore, 7 reservoir rock types were determined: - Anhydrite without reservoir quality, - limy– dolomite with mud dominated fabric without reservoir quality, - limy– dolomite with mud dominated fabric and an average reservoir quality, -limy– dolomite with mud dominated fabric and good reservoir quality, - dolomite with crystalline fabric and low reservoir quality, - limestone with grain dominated fabric with an average reservoir quality and - dolomite with crystaline fabric with a good reservoir quality. Based on petrophysical logs(Gamma ray, sonic, neutron & density), 5 reservoir units and 6 non – reservoir units were identified. Reservoir units are mainly formed of porous grain dominated limestone ,crystalline dolomite and mud dominated fabric dolomite, and non – reservoir units include anhydrite and limy dolomite without porosity. Petrophysical and petrographical studies indicate that moldic, intercrystaline and interparticle porosities are the most effective porosities in the reservoir units of this formation, whereas others like vuggy , fracture and intraparticle porosities have minor role in reservoir quality. Manuscript profile

Open Access Article

7 - Reservoir fluid type identification from petrophysical logs using pattern recognition methods
امیر ملا جان حسین معماریان بهزاد تخم چی

Identifying the type and distribution of reservoir fluids is one of the main things on well logging logs and well testing. Several methods have been proposed to identify the type of reservoir fluids that in general, it can be divided into two groups of methods; direct ( More

Identifying the type and distribution of reservoir fluids is one of the main things on well logging logs and well testing. Several methods have been proposed to identify the type of reservoir fluids that in general, it can be divided into two groups of methods; direct (e.g. well testing) and indirect methods (e.g. seismic and log interpretation). Petrophysical logs due to their high resolution and more conformity are more frequently used than seismic data. This study aims to identify reservoir fluid types in PLs, based on 3 classes of oil, oil-water and water, in carbon reservoir. Suggested method applies wavelet decomposition as well as classification and was applied to PLs in five wells of an oil field in southwestern Iran. Eventually, obtained results have been evaluated by well testing responses. Manuscript profile

Open Access Article

8 - Comparison of image log interpretation and core analysis advantages for study of fractures in hydrocarbon reservoir rocks: a case study in the Asmari reservoir Aghajari oil field
Masumeh Vatan dust Ali Farzipour Saein Esmaeil Salarvand

The Oligo-Miocene Asmari Formation is one of the main reservoir rocks of SW Iran with several decades of production history from different oil fields in the Zagros fold- thrust belt. One of the main reasons for the high quality of the Asmari reservoir is well develope More

The Oligo-Miocene Asmari Formation is one of the main reservoir rocks of SW Iran with several decades of production history from different oil fields in the Zagros fold- thrust belt. One of the main reasons for the high quality of the Asmari reservoir is well developed fracture system in this formation. Characteristics of fractures such as type, opening and orientation can be determined by the core analysis and also interpreting the image logs. This paper attempts to compare the advantages of the image log and core analysis in detecting fractures and other geological feathers in different zones of the Asmari Formation. To achieve this goal, we have compared the image log and core of well no. 89 of the Aghajari oil field. Comparison of the core well no. 89 of the Aghajari oil field with its image log revealed distinguish of the bedding planes in the core easier and more reliable than the image log. This study demonstrates the image log is more capable than core to detect the open fractures, while it is not suitable for detecting filled fractures. Indeed, image log rarely can detect shear fractures, but if it is calibrated with core, it can detect shear fractures with reasonable accuracy. Manuscript profile

Open Access Article

9 - Geochemical study of Tar-mat formation in Bangestan reservoir in Kupal oil field

Kupal anticline is elongated and almost symmetric. This structure is located in Northwest of Ahwaz city and consists of two reservoir including Bangestan and Asmari. Kazhdumi, Pabdeh and Gurpi formations are probable source rocks and Gachsaran Formation constitutes the More

Kupal anticline is elongated and almost symmetric. This structure is located in Northwest of Ahwaz city and consists of two reservoir including Bangestan and Asmari. Kazhdumi, Pabdeh and Gurpi formations are probable source rocks and Gachsaran Formation constitutes the cap rock. Because project topic is defined on Bangestan Group, so reservoir studies of Bangestan is focused on Sarvak Formation. Rock-Eval and geochemical analyses conducted on source rocks indicated that Pabdeh Formation is at early stage of oil generation window in the Kupal oil field. Kazhdumi Formation has not been drilled at this field, so geochemical and maturity assessment of this formation has been evaluated using samples from adjacent oil fields including Marun and Haftgel. Geochemical analyses indicated that Kazhdumi Formation is mature enough and is considered to be the main source rock. The aim of this project is investigating Tar-mat in Bangestan reservoir in Kupal field. It is thought that Tar-mat layer was formed in vicinity of oil-water contact and can be related to processes including natural deasphaltening, gravity segregation and oil-mixing. Based on Rock-Eval pyrolysis, pyrolysis-GC performed on Sarvak oil, it is suggested primary asphaltene formed from source rock does not exist in the studied oil but it is derived from secondary asphaltene by chemical reactions occurring due to oil-mixing in production well. In addition, analysis performed on asphaltene in oil zone, oil-water contact and water zone suggest that Tar-mat was formed in oil water contact region due to oxidation process. This layer acts as impermeable seal and prevents water flow to oil Manuscript profile

Open Access Article

10 - Geochemical evaluation of the Sarvak and Fahliyan reservoirs crude oils by biomarker data in one of the Abadan Plain oilfields
ELham Asadi. Mehmandosti Seyed Ali Moallemi Mahnaz amirhoseyni Azizolah Habibi

In this study, 8 crude oil samples of the Sarvak (5 samples) and Fahliyan (3 samples) reservoirs from one of the main oilfields of the Abadan Plain was assessed geochemically by Liquid Chromatography, Gas Chromatography (GC) and Gas Chromatography Mass Spectrometry (GC- More

In this study, 8 crude oil samples of the Sarvak (5 samples) and Fahliyan (3 samples) reservoirs from one of the main oilfields of the Abadan Plain was assessed geochemically by Liquid Chromatography, Gas Chromatography (GC) and Gas Chromatography Mass Spectrometry (GC-MS) techniques. Types of crude oils of the Sarvak reservoir are Paraffinic Naphtenic and Aromatic Intermediate and are Paraffinic type for the Fahliyan reservoir crude oils. Biomarker ratios of saturate fractions such as variation of Pr/nC17 and Ph/nC18 ratios and Pr/Ph versus C27/C29 (20R) Sterane diagram indicate formation of source rock in reducing marine environment for both oil reservoirs. Furthermore, high amount of C29 Sterane in compare to C27 and C28 Steranes show that organic matter of source rock was formed in marine environment with terrestrial kerogen input. High amount C29 Hopane versus C30 Hopane, variation C27 (Dia/Dia+Reg) Steranes versus Pr/(Pr+Ph), low amount of Diasteranes versus Steranes and variation Sterane/Hopane versus C27/C29 Steranes show carbonate- shale lithology for source rock of studied oils. Depending on high amount of resin, scattering of normal alkanes, high values of Pr/nC17 and Ph/nC18 and higher UCM in compare to other samples, K11 and K15 samples of the Fahliyan reservoir and B5 sample of the Sarvak reservoir demonstrate slight to moderate biodegradation while B19 sample show very slight biodegradation. According to variation of Pr/nC17 vs. Ph/nC18, C29 Sterane 20S/(20S+20R) vs. C32 Hopane 22S/(22S+22R), C29 Sterane 20S/(20S+20R) vs. C29 Sterane αββ/(αββ+ααα) samples from both reservoirs denote early oil window formation. Samples from the Fahliyan reservoir have high thermal maturity in compare to the Sarvak reservoir samples. Manuscript profile

Open Access Article

11 - Geochemical evaluation of the Sarvak and Fahliyan reservoirs crude oils by biomarker data in one of the Abadan Plain oilfields
Seyed Ali Moallemi Mahnaz Amir hosyeni Azizolah Habibi

In this study, 8 crude oil samples of the Sarvak (5 samples) and Fahliyan (3 samples) reservoirs from one of the main oilfields of the Abadan Plain was assessed geochemically by Liquid Chromatography, Gas Chromatography (GC) and Gas Chromatography Mass Spectrometry (GC- More

In this study, 8 crude oil samples of the Sarvak (5 samples) and Fahliyan (3 samples) reservoirs from one of the main oilfields of the Abadan Plain was assessed geochemically by Liquid Chromatography, Gas Chromatography (GC) and Gas Chromatography Mass Spectrometry (GC-MS) techniques. Types of crude oils of the Sarvak reservoir are Paraffinic Naphtenic and Aromatic Intermediate and are Paraffinic type for the Fahliyan reservoir crude oils. Biomarker ratios of saturate fractions such as variation of Pr/nC17 and Ph/nC18 ratios and Pr/Ph versus C27/C29 (20R) Sterane diagram indicate formation of source rock in reducing marine environment for both oil reservoirs. Furthermore, high amount of C29 Sterane in compare to C27 and C28 Steranes show that organic matter of source rock was formed in marine environment with terrestrial kerogen input. High amount C29 Hopane versus C30 Hopane, variation C27 (Dia/Dia+Reg) Steranes versus Pr/(Pr+Ph), low amount of Diasteranes versus Steranes and variation Sterane/Hopane versus C27/C29 Steranes show carbonate- shale lithology for source rock of studied oils. Depending on high amount of resin, scattering of normal alkanes, high values of Pr/nC17 and Ph/nC18 and higher UCM in compare to other samples, K11 and K15 samples of the Fahliyan reservoir and B5 sample of the Sarvak reservoir demonstrate slight to moderate biodegradation while B19 sample show very slight biodegradation. According to variation of Pr/nC17 vs. Ph/nC18, C29 Sterane 20S/(20S+20R) vs. C32 Hopane 22S/(22S+22R), C29 Sterane 20S/(20S+20R) vs. C29 Sterane αββ/(αββ+ααα) samples from both reservoirs denote early oil window formation. Samples from the Fahliyan reservoir have high thermal maturity in compare to the Sarvak reservoir samples. Manuscript profile

Open Access Article

12 - Analysis of Electrical Rock Type Bangestan Reservoir in Marun Oil Field
Abouzar Mohsenipour Bahman Soleimani Ehsan Abharakpour Ghodratollah Nikkhah

Studies of the electrical Rock Type a very important role in the development process plays a field.In these studies, theporo-perm Cores data and well log data used for reservoir simulations. In the present research, the flow of four flow units was determined in the res More

Studies of the electrical Rock Type a very important role in the development process plays a field.In these studies, theporo-perm Cores data and well log data used for reservoir simulations. In the present research, the flow of four flow units was determined in the reservoir using porosity and permeability data from well logging core by regional index method. In some wells, using well logging the basic model of electrical rocktype was determined with three methods of MRGC, SOM, and DYNAMIC. The determined facies by different methods were correlated with the flow unit. Finally, SOM method was selected, which has the best concordance. The initially created electrofacieswere reduced to 4 electrofacies due to the similarity of some parameters such as effective porosity and gamma logging. To ensure the accuracy of the electrical rock type by neural networks, these electrofacies were correlated with capillary pressure data. After confirming the determined electrofacies by capillary pressure, these facies were propagated in other wells in this field. This created a model, which was able to separate different parts of the reservoir. In this model, different parts of the reservoir were determined in terms of reservoir quality. Manuscript profile

Open Access Article

13 - Relation between microfacies, depositional environment and diagenesis with reservoir quality the Jahrum Formation in well no. 11, Golkhary oil field, Zagros basin
Maryam Sinapour Naser Arzani

In this study the relationship between petrographic studies (microfacies, environment of deposition and diagenesis) and petrophysical data of core analysis in order to identify reservoir quality of the Jahrum Formation in well no. 11 at the Golkhary oil field. The Go More

In this study the relationship between petrographic studies (microfacies, environment of deposition and diagenesis) and petrophysical data of core analysis in order to identify reservoir quality of the Jahrum Formation in well no. 11 at the Golkhary oil field. The Golkhary oil field is located at the west of Qatar-Kazerun fault, in between Binak and Nargesi oil fields. The Jahrum Formation consists of limestone, dolomite limestone and dolomite. Petrographical studies accomplish in two parts microfacies studies led to the recognition of 9 microfacies that were deposited in 3 facies belt tidal flat, lagoon and open marine environment. In diagenesis studies the most important factors included bioturbation, micritization, mechanical compaction, secondary porosity, secondary anhydrite cement, calcite burial cement, stylolites and solution seams, replacement dolomite, dolomite cement and hydrocarbon shows. Porosities identified are intercrystalline, intergrain, intrafossil and intragrain, moldic, fracture, solution along stylolite, solution enlarge and shelter. The results of this study shows that Grain supported MF3 (Bioclast Nummulitidae Rotalia wackestone/ packstone/ grainstone) and MF4 (Bioclast Nummulitidae Orbitolites packstone/ grainstone/ floatstone) due to the presence in the environment energetic, micrite absence, lack of widespread cement, presence of effective porosities includes intergrain porosity and intercrystalline porosity identified are reservoir microfacies. Petrophysical data with high levels of permeability and effective porosity between these two microfacies is the confirmation of the results of petrographic studies. Manuscript profile

Open Access Article

14 - Al Khalij field in Qatar, and extension toward Reshadat Oil Field, in the Persian Gulf
Ali reza Bashari

Alkhalij field located offshore Qatar , was discovered in 1991 and put into production in 1997. The field is original in many aspects. it is one of the few carbonate reservoir with stratigraphic closure, the oil is being trapped in upper part of a monocline due to a l More

Alkhalij field located offshore Qatar , was discovered in 1991 and put into production in 1997. The field is original in many aspects. it is one of the few carbonate reservoir with stratigraphic closure, the oil is being trapped in upper part of a monocline due to a lateral variation in reservoir facies. In addition, the reservoir lies within the capillary transition zone and consists of a succession of highly conductive oil bearing layers ( drains) in between matrix layers of poor permeability. High- resolution 3D seismic has revealed additional area developed, which were previously considered to be uneconomic. Resent 4D seimic pilot has given encouraging result to utilize Seismic Technologies to analyse the evolution of the Al Khalij oilfield over time. Studies shows, this field possibly extended toward Reshdat oil field. Manuscript profile

Open Access Article

15 - 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

16 - A case study of carbonate reservoir permeability determination using NMR log in one of the southwestern fields of Iran
Bahram Habibnia

Permeability is one of the most important parameters for characterization of hydrocarbon reservoirs that has a basic role in almost all of the petroleum engineering problems. Determination of reservoir permeability is usually done in core laboratories in a time consumin More

Permeability is one of the most important parameters for characterization of hydrocarbon reservoirs that has a basic role in almost all of the petroleum engineering problems. Determination of reservoir permeability is usually done in core laboratories in a time consuming process. In the well test, the obtained average permeability is related to the drainage area. Due to cost, these two methods are not performed in the all wells, whereas well logging tools are generally performed in all wells. With progress of well logging tools, some researchers tried to estimate permeability from special well logs such as NMR directly. The data obtained from NMR was used as lithology independent data to estimate the water saturation and porosity, and also for analysis of pore space. One of the important parameters obtained from NMR is the transversal relaxation time (T2). In this work, NMR log measurement in a carbonate field was used to estimate the permeability using Timur, SDR and regression models. The results of the methods were compared against core permeability. The results show that SDR method is more accurate with the accuracy of 44.1% and the error of 23.12%. Manuscript profile

Open Access Article

17 - Study the role of drilling mud loss modeling and FMI log in determining Asmari reservoir fractures in one of the oil fields in Southwest Iran
Kioumars Taheri Mohammad Reza Rasaei Abbas Ashjaei

Understanding of oil and gas reservoirs is of great help in maximizing hydrocarbon recovery. In the study of the characteristics of oil structures, the study of fractures of reservoir rock in the stages of production and development of the field is very necessary. Nowad More

Understanding of oil and gas reservoirs is of great help in maximizing hydrocarbon recovery. In the study of the characteristics of oil structures, the study of fractures of reservoir rock in the stages of production and development of the field is very necessary. Nowadays, the use of mud loss modeling and image logs in helping accomplish this task is of great assistance to oil geologists. Since the most of Iran's reservoirs are carbonate kind, investigating and identifying fractures, the degree of fissures opening and porosity distribution in the Asmari reservoir field of study, It is one of the most effective factors in the production of hydrocarbons from this field. One of the best ways to identify and interpret geology in the well, using of the FMI image log is, which can create high quality images from the well. With the help of the images provided, can determine the types of fractures, porosity, the distribution of diagenetic porous spaces and the estimation of permeability trend. In this article, first, structure and Functionality of the FMI image log and then drilling and production problems were evaluated in Asmari reservoir. In the following, the functional role of the log in interpreting and determining the degree of fissures opening, porosity distribution and permeability level in 8 wells in Asmari reservoir, has been evaluated. In this study, identification of Asmari reservoir fractures and how to expand these fractures in the reservoir By using mud loss modeling, interpretation of the FMI image log and the effect of these fractures was on the porosity and permeability of the reservoir. In this study, it has been determined that, fractures identified in wells very good matching with drilling mud loss maps with rock basement faults at the has anticline of the Asmari reservoir. Manuscript profile

Open Access Article

18 - Facies, thickness variations and reservoir characterisation of Arab formation (Surmeh) in the Eastern part of the Persian Gulf
Ali reza Bashari

The Kimmerigian-Tithonian) Arab Zone are the prolific hydrocarbon bearing resrvoirs in the eastern part of the Persian Gulf,offshore,Iran.They were deposited in an arid climate which dominate during late Jurassic. The Berriasian to Thitonian Hith formation wich o More

The Kimmerigian-Tithonian) Arab Zone are the prolific hydrocarbon bearing resrvoirs in the eastern part of the Persian Gulf,offshore,Iran.They were deposited in an arid climate which dominate during late Jurassic. The Berriasian to Thitonian Hith formation wich overlies the Arab reservoir constitutes the cap rock,wich just to the east gradually pinches out and form a N-S feather adge. The study reveals that Arab zones form a massive to interbedded anhydrite with varying proportion of limestone and dolomite and generally have regressive units which was deposited on a broad carbonate platform .This formations are thick in center (Salman field) and mostly consist of intertidal pack/grainstones with high porosity/permeability,good cap rock and also close to the source rock,which has the most hydrocarbon potential, but towards east the layers getting thinner with unsuitable cap rock and are away from source rock ,so as a result Arab formation in this part of the Persian Gulf doesn,t seem to be attractive. This study reveals that there is still some undrilled structure within this area which could be attractive for further Exploration drilling. Manuscript profile

Open Access Article

19 - Enhancing volume and salinity of production water in oil and gas wells, Case study: Mozduran gas reservoir
rahim Bagheri Mehdi Miri Farshid khabiri Mohhamadreza Akhlaghi

The production of oil and gas in oil and gas fields is accompanied by production of water (Produced Water). Most of the reservoirs at the beginning of production have fresh water; but with passing time due to the increase in productions and decrease in pressure of reser More

The production of oil and gas in oil and gas fields is accompanied by production of water (Produced Water). Most of the reservoirs at the beginning of production have fresh water; but with passing time due to the increase in productions and decrease in pressure of reservoir, the produced water gradually becomes saline. The saline Production water causes severe corrosion in pipelines and well head facilitis leading to reduction in gas production. Determining the origin of salinity for reducing the salinity is most important. Khangiran gas field is located in the northeast of Iran which composed of two separate gas formations, Mozduran at lower and Shurijeh at the upper part. The produced water samples were collected from fresh and salty wells in the Mozduran reservoir as well as two deep samples from brine below the gas reservoir (at depth of 3 km) for comparison and different analyzes. The Mozduran reservoir has two major problems, high salinity of the produced water, as well as the volume of water produced, rendering some wells unexploitable. The results revealed that two deep water samples have different behaviors. The deep sample No. 17, taken at a higher elevation than sample No. 13, showed the signs of salt dissolution; whereas the brine from sample no.13 had the origin of the evaporated old sea water. Therefore, any of these brines in the Khangiran reservoir can be the possible source of salinity in produced waters. The saline produced water samples showed a similar behavior to brine sample no.13. The source of fresh produced water is also the condensation of water vapor in the reservoir during production. Manuscript profile

Open Access Article

20 - Effect of sequential pressure on petrophysical properties of carbonate reservoir rocks
Ali Moradzadeh yaser Salimidelshad Ezatollah Kazemzadeh abbas Majdi

Today, oil industry significantly relies on the precise determination of rock reservoir properties, which reduces the costs and risks of production planning. The reservoir rock always is compacted by pressure drop of the reservoir, which rises effective stress, reservoi More

Today, oil industry significantly relies on the precise determination of rock reservoir properties, which reduces the costs and risks of production planning. The reservoir rock always is compacted by pressure drop of the reservoir, which rises effective stress, reservoir compaction and alterations of reservoir properties. As these pressure variations can considerably affect petrophysical properties, in this study, several carbonate reservoir rock samples with different fabric and porosity type (according to CT scan and Archie classification analysis) subjected to cyclic and short-term loading from 600 to 6000 psi. Their petrophysical and compressive properties including pore volume, permeability and compressibility were measured using CMS-300 apparatus. Moreover, structural analysis and heterogeneity of core samples were analyzed by CT scan images. By performing this study, it will be possible to identify the value of the hysteresis effect on the reservoir rock samples as a result of increasing and decreasing of the pressure during cyclic loading. The obtained results show that, pore volume and permeability are both decreased due to loading, whereas reduction of the permeability is several times than the pore volume ones. Moreover, this reduction of pore volume is less severe in vuggy porous samples that shows the effect of heterogeneity and porosity type on hysteresis. Also, the results obtained from the behavior of the reservoir rock under various pressure conditions can provide a suitable design for gas injection studies to enhance oil recovery and also natural gas storage. Manuscript profile

Open Access Article

21 - The impact of microfacies and diagenesis characteristics on the reservoir quality of Asmari Formation in the Gevarzin gas field, Zagros basin, south Iran
Karim Mombani Ahmad Yahyaei

Asmari Formation from the Gavarzin gas field have erosional unconformity boundary on marl and pelagic limestones of Pabdeh Formation and gradually change to evaporate cap rock of Gachsaran Formation. Cores studies from the one of wells of Gavarzin field is 183 m in thic More

Asmari Formation from the Gavarzin gas field have erosional unconformity boundary on marl and pelagic limestones of Pabdeh Formation and gradually change to evaporate cap rock of Gachsaran Formation. Cores studies from the one of wells of Gavarzin field is 183 m in thickness, which includes 1.30 m from the top of Pabdeh, 162.4 m from the Asmari Formation and 19.30 m from the base layers of Gachsaran. Asmari Formation includes alternation of limestone, calcite dolomitic, claystone and shale with green marl. Petrology and facies analysis of the sequence of these formations identified 12 microfacies, a carbonate ramp from deep-sea to sabkha environments and formed in a retrograded sequence. This ramp includes deep environments, open sea, patch reef, bio-, clastic-bars, lagoon and tidal environments, which confirms a changing environment due to rapid facies changes and deposition of evaporative sediments in Gachsaran as a restricted environment. Diagenesis processes are considered as the main factors in carbonate reservoir quality of Gavarzin field. The diagenesis history of the Asmari carbonates of the studied cores is summarized as A) marine phreatic diagenesis, bioturbation, micritization and cementation processes occurred. B) vadose zone diagenesis, where the crystallization, cementation, and dissolution occurred. C) burial diagenesis, comprises compression-induced, pressure dissolution and fracturing are common. The microfacies show a wide varieties of reservoir characteristics and therefore a heterogeneous reservoir has been formed. Micro-fractures, however have strongly influence on the reservoir quality in the section. The simultaneous presence of dissolved spaces and fractures in the reservoir the permeability greatly increased. The best reservoir quality in the Grainstone/Packston facies are coated grains with moldic porosity that were created by the leaching of Ooid-bearing Packston lithology during the diagenesis of atmospheric waters. Manuscript profile

Open Access Article

22 - 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

23 - 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

24 - An attempt to reservoir characterization of Burgan sand, in the northwest of the Persian Gulf toward Kuwait
Ali reza Bashari

The Sand tongues of the Albian Kazhdumi Formation is a major prodactive reservoir in North West part of the Persian Gulf towards Kuwait . High porosity and high permeability of these sandstones together with existence of shale either as source rock or cap rock in More

The Sand tongues of the Albian Kazhdumi Formation is a major prodactive reservoir in North West part of the Persian Gulf towards Kuwait . High porosity and high permeability of these sandstones together with existence of shale either as source rock or cap rock in this formation, have provided all conditions needed for hydrocarbon accumulation. A rapid sea level fall in ealry Albian initiated the deposition of Burgan clastic reservoirs over the Shuaiba Carbonates. The lower Burgan Formation was deposited in a lowstand systems tract represented by massive sandstone reservoirs. High frequency sealevel changes have resulted in deposition of shoreface sands and extensive marine shales within an overall fluvial setting. The middle part Burgan was deposited in a transgressive systems tract. The upper part witnessed a relative sealevel fall in a lowstand systems tract with deposition of sand prone facies in estuarine channels. The clastic cycle was terminated by initiation of Mauddud carbonate sedimentations in transgressive systems tract. A combined effect of allocyclic nesting of sequence stratigraphic packages and autocyclic ramp profile were the primary factors controlling the lithofacies association. This Formation has been informally subdivided into: Lower Interval (C) mainly shaly sands, middle Interval (B) clean sands “main reservoir” and upper Interval (A) interbedded shale & sands. Petrographic analysis shows that the reservoir consists of quartz-rich sands, (typically>70%) and feldspar poor (mainly <5%). Nine authigenetic minerals in the Burgan sands have been identified: quartz, calcite, siderite, pyrite, glauconite along with four groups of the clay minerals. XRD analysis of clay fraction indicates the presence of four clay mineral groups in the Burgan reservoirs : kaolin, illite , chlorite and expandible- lattice mixed –layer, illite/ smectite. Manuscript profile

Open Access Article

25 - Permeability estimation using petrophysical logs and artificial intelligence methods: A case study in the Asmari reservoir of Ahvaz oil field
Abouzar Mohsenipour Bahman Soleimani iman Zahmatkesh Iman Veisi

Permeability is one of the most important petrophysical parameters that play a key role in the discussion of production and development of hydrocarbon fields. In this study, first, the magnetic resonance log in Asmari reservoir was evaluated and permeability was calcula More

Permeability is one of the most important petrophysical parameters that play a key role in the discussion of production and development of hydrocarbon fields. In this study, first, the magnetic resonance log in Asmari reservoir was evaluated and permeability was calculated using two conventional methods, free fluid model (Coates) and Schlumberger model or mean T2 (SDR). Then, by constructing a simple model of artificial neural network and also combining it with Imperialist competition optimization (ANN-ICA) and particle swarm (ANN-PSO) algorithms, the permeability was estimated. Finally, the results were compared by comparing the estimated COATES permeability and SDR permeability with the actual value, and the estimation accuracy was compared in terms of total squared error and correlation coefficient. The results of this study showed an increase in the accuracy of permeability estimation using a combination of optimization algorithms with artificial neural network. The results of this method can be used as a powerful method to obtain other petrophysical parameters. Manuscript profile

Open Access Article

26 - 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

27 - 3D modeling of rock types using the integration of core, well logs and seismic data in one of the carbonate reservoirs of southwestern Iran.
Mahdi Kheirollahi Golnaz Jozanikohan Reza Mohebian Ali Moradzadeh

10.52547/ispg.38414.11.21.1

Rock typing is the process of assigning reservoir properties to geological facies, and an identified rock type has similar geological and reservoir properties. Due to the importance of identifying and separating rock types in hydrocarbon reservoirs, various methods have More

Rock typing is the process of assigning reservoir properties to geological facies, and an identified rock type has similar geological and reservoir properties. Due to the importance of identifying and separating rock types in hydrocarbon reservoirs, various methods have been proposed and developed today for the determination of rock types. One of the simplest methods is the porosity chart against permeability and cut-off determination, and one of the most important and practical of these methods is to determine rock types by flow zone indicator. In this study, we examine one of the most important hydrocarbon fields in the south of Iran where core, well and seismic data are available for the field studied so that by designing a new workflow and with use of the most important and efficient methods of rock typing, including FZI, porosity, Winland-Pitman index, FZI*, and logarithms of FZI and FZI* we have identified rock types in three dimensions and through the whole field. After the final validation, the correlation coefficient values were more than 83%, 57%, 70%, 70%, 73% and 78% for the methods used, indicating greater accuracy and efficiency of the FZI method for the rock types separation in this field. The partial comparison of the validation results after each method employment also confirms the highest accuracy belongs to the FZI method. As a result, by integrating this method with seismic attributes, the rock types have been separated in four different groups throughout the field in three dimensions. Manuscript profile

Open Access Article

28 - 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 Mehdipour

10.52547/ispg.39683.11.21.16

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 on More

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. Manuscript profile

Open Access Article

29 - 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

30 - 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

Open Access Article

31 - Reservoir characteristics prediction using the geostatistical model. Case study: Bangestan reservoir, Ziloi Field, SW Iran
Somaieh Khoram abadi Bahman Soleimani Hussin Sheikhzadeh

The 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 More

The 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

32 - Hydrodynamic and Hydrochemical Study in Oil Reservoirs: Asmari reservoir, Rag-E-Safid Oil Field
بهمن سلیمانی abdolah Momeni Faizhabad Mousa Zohrabzadeh

The evaluation of hydrodynamic characteristics can be a useful tool to understand the field behavior and production efficiency. The present study is an attempt to clarify hydrodynamic flow in the Asmari reservoir of the Rage Safid oil field. Water oil contact (WOC) dept More

The evaluation of hydrodynamic characteristics can be a useful tool to understand the field behavior and production efficiency. The present study is an attempt to clarify hydrodynamic flow in the Asmari reservoir of the Rage Safid oil field. Water oil contact (WOC) depth is 200m lesser in northern flank than southern part. The results indicated that the aquifer potentiometric surface is tilted. The Piper and Composition diagrams are showing the mixing process of two water types including Cl-Na type with higher TDI and calcic-magnesic bicarbonate type with lower TDI in the reservoir water. The first one is sourced from salt horizons of Gachsaran Formation and the second one is from limestone-dolomitic parts of the Asmari Formation. This result is also verified by TDI to depth plot. Hydrodynamic maps and fluids trends are showing a continuous flow from NE to W-SW of the field. This flow is relatively strong in western and south western part. Generally, production index and pressure data indicate a suitable condition in southern –southwestern part of the field. By considering fluid flux from NE to W-SW it is strictly proposed to focus drilling program in the western part and the water injection program in the north eastern part of the field. Manuscript profile

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