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      • Open Access Article

        1 - 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

        2 - 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
        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