فهرست مطالب سیامک مرادی

In engineering projects (dams, tunnels, and slope stability) the strength properties of the rocks affect the construction operations. In some cases, conducting field experiments is difficult, time-consuming, and expensive. Therefore, researchers have introduced practical relationships for predicting strength properties of rocks (e.g. uniaxial compressive strength (UCS)). Uniaxial compressive strength is one of the most important rock parameters in studies of rock mechanics. This parameter can be determined directly in the laboratory or can be estimated through indirect methods like the Schmidt hammer. The estimation of uniaxial compressive strength via the number of Schmidt hammer is easier, faster, and cheaper than a direct measurement. The major purpose of this study is to analyze the relationships between the uniaxial compressive strength of rocks with the Schmidt stiffness. In this research, three samples of rock have been studied including Aghajari sandstone, Qom marly formation, and Karaj tuff. With respect to the importance of this subject in this study, new practical relationships have been presented to calculate uniaxial compressive strength whose application show desired results. In order to achieve this aim, the most appropriate and logical relationships between Schmidt hardness tests with uniaxial compressive strength has been introduced by the regression method. The relationships between uniaxial compressive strength, the Schmidt hammer, and dry density of rock have been evaluated by simple and multiple regression (SR/ MR) techniques using Minitab 19 software. The statistical analyses revealed the existence of powerful correlations between the uniaxial compressive strength, Schmidt hardness features of rocks, and dry density in samples of sandstone, marl, and tuff. According to this study, multivariate regression presents more credible results. 

Enhanced oil recovery (EOR) methods are employed for increasing oil recovery after natural production of the reservoir. Each EOR process has limitation for applying in reservoirs due to rock and fluid condition. In water alternating gas (WAG) flooding, many parameters such as reservoir thickness, horizontal permeability, connate water saturation effect on oil recovery factor. In this study, main parameters that effect on WAG oil recovery were discussed using fraction factorial design and simulation. The CMG-GEM was used for simulation study. The Minitab statistical experimental design software was used for stochastic analysis. The results show reservoir thickness, connate water saturation, and the interaction of two parameters reservoir dip angle and horizontal permeability had main effect on oil recovery factor. Finally, a regression model based on the effective parameters was obtained. This regression model can be used to estimate the oil recovery during WAG flooding. According to the results of this study, the performance of WAG process in different candidate reservoirs can be predicted and one can rank the reservoirs to select the one with maximum recovery factor for further detailed reservoir and pilot studies.

One of the common methods for reservoir screeining in EOR projects is comparison of prosperous projects is comparison between successfulcarried out projects and available reservoirs in the whole world. Because of lack of similar samples in this method, some of reservoirs are not considered for injection, so casing of another EOR method is necessary. In this paper, at first, by combination of Experimental design and Compositional simulation, rock and fluid effective parameters are detected in N2 and CH4 gas injections for pressure maintenance in reservoirs. Then, indirect and interaction effect of these parameters are analyzed and compared for both gas injections. separately for both gases injection are analyzed and compared. Finally, for estimation of oil recovery factor, empirical correlation is proposed. This correlation is used for primary screening in N2 and CH4 injection projects.