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      • Open Access Article

        1 - Study of Petrography & Petrophysics of Permian- Triassic carbonate sediments in Qatar –South Pars Arch
        Ali reza Bashari
        Abstract Dalan and Kangan Formations are major gas reservoirs in the Persian Gulf and surrounding area. Several supper giant gas fields has been found in the region. In this study reservoir rock types were identified and were divided into four lithostratigraphic zo More
        Abstract Dalan and Kangan Formations are major gas reservoirs in the Persian Gulf and surrounding area. Several supper giant gas fields has been found in the region. In this study reservoir rock types were identified and were divided into four lithostratigraphic zones: K1 to K4. Each of the four succeeding zones have been divided into different subzone. This Studies identified different facies-types on the Dalan and Kangan formation in this region. Petrophysical & Petrographycal studies indicate that the best reservoir unites are found in: Dolo-grainstones, Dolowakestones/Packstones and Grainstones. Isopach maps and Depth maps show variations in thickness and depth of different zones in this region. Depth map on top of Kangan formation shows this formation getting deeper toward north- west and south east in the Persian Gulf. Continuity of marker beds in Permian/Triassic sediment and paleontological evidence support diachroneity of these sediments. Manuscript profile
      • Open Access Article

        2 - The application of clustering methods (MRGC, AHC, DC, SOM) determining permeability carbonate reservoir rocks Ilam Formation in South West Iran
        Seyed Ali Moallemi farhad khoshbakht sakineh naghdi
        The permeability of reservoir parameters is important in the calculation and modeling reservoir plays a role. Measured directly via cores taken from the reservoir layer can be achieved. But due to the limited amount of core taken in a field and laboratory methods as wel More
        The permeability of reservoir parameters is important in the calculation and modeling reservoir plays a role. Measured directly via cores taken from the reservoir layer can be achieved. But due to the limited amount of core taken in a field and laboratory methods as well as high cost; use indirect methods to determine the wells without core permeability is great value. In this study, using clustering methods using petrophysical logs permeability values were measured and analyzed. For this purpose, petrophysical logs Ilam Formation selection of 8 wells and addition of data measured in vitro permeability 3-ring is used to compare the results. Log permeability effective porosity in the well using the parameters A with the core permeability data, estimates and then check the accuracy of estimates, calculations also took place in other fields of study. In the next step, using clustering method, was estimated permeability. Then the results with experimental data and correlation coefficient, the best method is introduced. Manuscript profile
      • Open Access Article

        3 - 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

        4 - Designing an Ensemble model for estimating the permeability of a hydrocarbon reservoir by petrophysical lithology Labeling
        abbas salahshoor Ahmad Gaeini Alireza shahin mossayeb kamari
        Permeability is one of the important characteristics of oil and gas reservoirs that is difficult to predict. In the present solution, experimental and regression models are used to predict permeability, which includes time and high costs associated with laboratory measu More
        Permeability is one of the important characteristics of oil and gas reservoirs that is difficult to predict. In the present solution, experimental and regression models are used to predict permeability, which includes time and high costs associated with laboratory measurements. Recently, machine learning algorithms have been used to predict permeability due to better predictability. In this study, a new ensemble machine learning model for permeability prediction in oil and gas reservoirs is introduced. In this method, the input data are labeled using the lithology information of the logs and divided into a number of categories and each category was modeled by machine learning algorithm. Unlike previous studies that worked independently on models, here we were able to predict the accuracy of such a square mean error by designing a group model using ETR, DTR, GBR algorithms and petrophysical data. Improve dramatically and predict permeability with 99.82% accuracy. The results showed that group models have a great effect on improving the accuracy of permeability prediction compared to individual models and also the separation of samples based on lithology information was a reason to optimize the Trojan estimate compared to previous studies. Manuscript profile
      • Open Access Article

        5 - 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