Nader Fathianpour - Academia.edu (original) (raw)
Papers by Nader Fathianpour
Archives of Mining Sciences, 2011
Determination of the pit limits is a vital task in the designing process of a mine. While overest... more Determination of the pit limits is a vital task in the designing process of a mine. While overestimation increases stripping ratio, underestimation can result in loss of economic ore. The available methods of pit limit optimization are mostly based on the programming approaches (linear and/ or dynamic) and graph theory. In the large scale mines with probably varying wall slopes especially in 3D states performance of these approaches may be unsatisfactory. In this paper, a new 3D pit optimization algorithm has been developed and applied in an economic classified block model. In the first step economic block model of the Esfordi phosphate mine (Iran) was prepared. In the second step, the block model was divided into positive and negative regions with the help of a well trained feed-forward back-propagation neural network. For this, 3D blocks coordinates were considered as the neural network inputs whereas the blocks net economic values were set to be the model output. Finally, the opt...
ABSTRACT It is about 30 years that Helicopter electromagnetic (HEM) surveys are being used for ra... more ABSTRACT It is about 30 years that Helicopter electromagnetic (HEM) surveys are being used for rapid mineral and ground water exploration, environmental investigations and also geological mapping in extensive areas. Despite this, one of the most important problems in using obtained data from the surveys is accurate interpretation of the data. Otherwise, there will be no beneficial results while spending high costs. Thus the interpretation of the data is as old as the surveys. Several experts have been tried to improve the interpretation of HEM data and they have achieved great successes. Almost the results of all these surveys are presented as resistivity (or conductivity)-depth sections. To reach this target, the first step is to solve the electromagnetic induction integral equation. As solving this integral is not possible using analytical methods, several numerical methods such as Laplace transformation, Hankel transformation and Jacobi-Matrix methods have been suggested for the solution of the integral, and different approaches have been presented with each method by various authorities. One of the most important solution methods is fast Hankel transformation. In this paper, it is attempted to use this method for finally obtaining resistivity-depth sections. For solving the induction equation by this method, we need the kernel function of the integral and weighting coefficients that replace the Bessel function in the integral. For this, first we use the Guptasarma-Singh method. Then results of this method are corrected and evaluated. Then, these results will be analyzed and tested with two synthetic models in addition to presenting the results of inverse modeling. Finally, by adding new parameter named α0 to induction equation, we will clearly see an improvement in the results of inverse modeling. Meanwhile, the problem of singularity that occurs at high frequencies is almost removed.
Due to the need for greater depth of investigation in petroleum and geothermal exploration and th... more Due to the need for greater depth of investigation in petroleum and geothermal exploration and the complexity of the associated geological models often involved in any interpretation of magnetotelluric data, it would be inevitable to employ a * دشرا سانشراك ** رايشناد
Mineral exploration is a complex, time consuming and risky process. Reducing the risk level has a... more Mineral exploration is a complex, time consuming and risky process. Reducing the risk level has always been aimed by mineral explorers and managers. As for the all anomalies obtained from different exploration data are not showing mineralization, integrating of these anomalies are used to detemine the targets. Due to verification by different methods in such areas, the investment costs and risk will be low. The region which was investigated in this study was located at Kerman Cenozoic Magmatic Arc (KCMA). After prepation of geological, geochemical, geophysical, faults and remote sensing layers, using basin sample catchment, reduce to pole and analytic signal, band ratio and spectral angle mapper methods, paired comparisons between layers were performed by AHP method and results were used for mineral potential mapping (MPM). Results of the method were in a good agreement with the known mineralization at the zone and there could be used as a way to determine the vein and porphyry type...
To date, a number of numerical methods, including the popular Finite-Difference Time Domain (FDTD... more To date, a number of numerical methods, including the popular Finite-Difference Time Domain (FDTD) technique, have been proposed to simulate Ground-Penetrating Radar (GPR) responses. Despite having a number of advantages, the finite-difference method also has pitfalls such as being very time consuming in simulating the most common case of media with high dielectric permittivity, causing the forward modelling process to be very long lasting, even with modern high-speed computers. In the present study the well-known hyperbolic pattern response of horizontal cylinders, usually found in GPR B-Scan images, is used as a basic model to examine the possibility of reducing the forward modelling execution time. In general, the simulated GPR traces of common reflected objects are time shifted, as with the Normal Moveout (NMO) traces encountered in seismic reflection responses. This suggests the application of Fourier transform to the GPR traces, employing the time-shifting property of the tran...
Journal of Molecular Liquids
Geothermics
Abstract This paper introduces a computational model based on the structural and petrophysical ch... more Abstract This paper introduces a computational model based on the structural and petrophysical characteristics of the high-enthalpy geothermal reservoirs. Conceptual model of the Sabalan geothermal field is provided through integrating the various exploring information including the structural data, geological data, geophysical models, well logs and field evidences. Heat source is properly estimated by implementing the Curie depth map. The finite element method, adapted to the complex geometry of the model, is used to solve the governing equations. All-important physical and structural properties of the reservoir including the anisotropic and heterogonous permeability distribution, fluid flow through the faults and specific boundary conditions are considered. Optimization analysis is conducted to calibrate the model parameters. Simulated thermodynamic properties of the reservoir are compared with the wellbore measured data to validate the results.
Geophysical Prospecting
Ground-penetrating radar is one of the most effective methods of detecting shallow buried objects... more Ground-penetrating radar is one of the most effective methods of detecting shallow buried objects. Ground-penetrating radar radargram is a vertical map of the radar pulse reflections that returns from subsurface objects, and in the case of cylindrical objects, it would be a hyperbola. In order to get clear and accurate information on the presence, location, and geometry of the buried objects, the radargrams need to be interpreted. Interpretation of the results is a time-consuming task and needs an expert with vast knowledge. Development of an automatic interpretation method of B-scan ground-penetrating radar images would be an effective and efficient solution to this problem. A novel automatic interpretation method of ground-penetrating radar images, based on simultaneous perturbation artificial bee colony algorithm using tournament selection strategy, simultaneous perturbation stochastic approximation method, and new search equations, is introduced in this paper. The proposed algorithm is used to extract geometrical parameters, i.e. depth, location, and radius, of buried cylindrical objects in order to assess its accuracy. Synthetic data, simulated using GprMax2D forward modelling program, and real data, surveyed in the campus of Isfahan University of Technology, are used in the assessment. The performance of the proposed method in detecting synthetic hyperbolas is compared with that of the original artificial bee colony algorithm, genetic algorithm, and modified Hough transform. The results show superiority of the proposed algorithm, in detecting synthetic hyperbolas. Furthermore, the performance of the proposed method in estimating depth and radius of pipes in real ground-penetrating radar images is compared with that of the modified Hough transform. The results indicate higher accuracy of the proposed method in estimating geometrical parameters of the buried cylindrical objects.
Journal of Water and Soil Science
In addition to kinematic description of biological reaction, flow pattern plays an important role... more In addition to kinematic description of biological reaction, flow pattern plays an important role in designing constructed wetlands. This study investigates the effects of flow distribution on constructed sub-surface horizontal flow wetland with a length of 26 m, width of 4 m and 1% bed slope in order to understand internal hydraulic functioning patterns. Inlet configuration is selected as a variable parameter. Three different cases of inlet and outlet configurations were 1) midpoint, 2) corner, and 3) uniform. Outlet has been fixed in all configurations. Uranine tracer was used to determine the influences of flow distribution by drawing hydraulic retention time curve in different cases. Results showed that mean residence times for each configuration were equal to 4.53, 3.24 and 4.65 days, respectively. Retention time distribution curve provided conditions, not only for showing dispersion patterns throughout system but also for interpreting hydraulic parameters like hydraulic efficiency and effective volume. According to the retention time curve, effective volume was 87.5% in configurations 1 and 3, and 62.1% in configuration 2 following numerous shortcircuiting ratios. Finally, the best configuration of inlet-outlet layout to improve the performance of effluent treatment and use the geometry effectively was found to be the uniform-midpoint based on physical experiments followed by midpoint-midpoint as the second best.
Renewable Energy, 2016
This paper introduces a computational model for transient high enthalpy fluid flow through geothe... more This paper introduces a computational model for transient high enthalpy fluid flow through geothermal wellbores. The drift-flux model is utilized to formulate the physical behavior of fluid, and the constitutive relationships are described using relevant equations of state and empirical relationships. The governing equations are solved using the finite element method. All important physical phenomena and processes occurring along the wellbore, including buoyancy, phase change, compressibility, thermal interaction, wall friction and slip between phases are considered. Airlifting of water and air, initially existing in the wellbore before production, is also considered. During airlifting and early stages of production, two fluids exist along the wellbore: airlifted water-dry air fluid, and reservoir water-vapor fluid; giving rise to a discontinuity in thermodynamic properties between the two fluids. The discontinuity is modeled using the level-set method. Two numerical examples illustrating the computational capability and accuracy of the model are presented. The physical phenomena occurring during airlifting and production along the wellbore are highlighted.
Computational Methods, 2006
The modified Finite Point Method (FPM) is considered as one of the latest developments among the ... more The modified Finite Point Method (FPM) is considered as one of the latest developments among the meshless numerical methods. In order to achieve accurate results using modified FPM, it is essential to impose suitable mixed Boundary Conditions (BC) along with simultaneously satisfying both the governing Partial Differential Equation (PDE) at internal nodes and the associated BC at the nodes located
Archives of Mining Sciences, 2011
Determination of the pit limits is a vital task in the designing process of a mine. While overest... more Determination of the pit limits is a vital task in the designing process of a mine. While overestimation increases stripping ratio, underestimation can result in loss of economic ore. The available methods of pit limit optimization are mostly based on the programming approaches (linear and/ or dynamic) and graph theory. In the large scale mines with probably varying wall slopes especially in 3D states performance of these approaches may be unsatisfactory. In this paper, a new 3D pit optimization algorithm has been developed and applied in an economic classified block model. In the first step economic block model of the Esfordi phosphate mine (Iran) was prepared. In the second step, the block model was divided into positive and negative regions with the help of a well trained feed-forward back-propagation neural network. For this, 3D blocks coordinates were considered as the neural network inputs whereas the blocks net economic values were set to be the model output. Finally, the opt...
ABSTRACT It is about 30 years that Helicopter electromagnetic (HEM) surveys are being used for ra... more ABSTRACT It is about 30 years that Helicopter electromagnetic (HEM) surveys are being used for rapid mineral and ground water exploration, environmental investigations and also geological mapping in extensive areas. Despite this, one of the most important problems in using obtained data from the surveys is accurate interpretation of the data. Otherwise, there will be no beneficial results while spending high costs. Thus the interpretation of the data is as old as the surveys. Several experts have been tried to improve the interpretation of HEM data and they have achieved great successes. Almost the results of all these surveys are presented as resistivity (or conductivity)-depth sections. To reach this target, the first step is to solve the electromagnetic induction integral equation. As solving this integral is not possible using analytical methods, several numerical methods such as Laplace transformation, Hankel transformation and Jacobi-Matrix methods have been suggested for the solution of the integral, and different approaches have been presented with each method by various authorities. One of the most important solution methods is fast Hankel transformation. In this paper, it is attempted to use this method for finally obtaining resistivity-depth sections. For solving the induction equation by this method, we need the kernel function of the integral and weighting coefficients that replace the Bessel function in the integral. For this, first we use the Guptasarma-Singh method. Then results of this method are corrected and evaluated. Then, these results will be analyzed and tested with two synthetic models in addition to presenting the results of inverse modeling. Finally, by adding new parameter named α0 to induction equation, we will clearly see an improvement in the results of inverse modeling. Meanwhile, the problem of singularity that occurs at high frequencies is almost removed.
Due to the need for greater depth of investigation in petroleum and geothermal exploration and th... more Due to the need for greater depth of investigation in petroleum and geothermal exploration and the complexity of the associated geological models often involved in any interpretation of magnetotelluric data, it would be inevitable to employ a * دشرا سانشراك ** رايشناد
Mineral exploration is a complex, time consuming and risky process. Reducing the risk level has a... more Mineral exploration is a complex, time consuming and risky process. Reducing the risk level has always been aimed by mineral explorers and managers. As for the all anomalies obtained from different exploration data are not showing mineralization, integrating of these anomalies are used to detemine the targets. Due to verification by different methods in such areas, the investment costs and risk will be low. The region which was investigated in this study was located at Kerman Cenozoic Magmatic Arc (KCMA). After prepation of geological, geochemical, geophysical, faults and remote sensing layers, using basin sample catchment, reduce to pole and analytic signal, band ratio and spectral angle mapper methods, paired comparisons between layers were performed by AHP method and results were used for mineral potential mapping (MPM). Results of the method were in a good agreement with the known mineralization at the zone and there could be used as a way to determine the vein and porphyry type...
To date, a number of numerical methods, including the popular Finite-Difference Time Domain (FDTD... more To date, a number of numerical methods, including the popular Finite-Difference Time Domain (FDTD) technique, have been proposed to simulate Ground-Penetrating Radar (GPR) responses. Despite having a number of advantages, the finite-difference method also has pitfalls such as being very time consuming in simulating the most common case of media with high dielectric permittivity, causing the forward modelling process to be very long lasting, even with modern high-speed computers. In the present study the well-known hyperbolic pattern response of horizontal cylinders, usually found in GPR B-Scan images, is used as a basic model to examine the possibility of reducing the forward modelling execution time. In general, the simulated GPR traces of common reflected objects are time shifted, as with the Normal Moveout (NMO) traces encountered in seismic reflection responses. This suggests the application of Fourier transform to the GPR traces, employing the time-shifting property of the tran...
Journal of Molecular Liquids
Geothermics
Abstract This paper introduces a computational model based on the structural and petrophysical ch... more Abstract This paper introduces a computational model based on the structural and petrophysical characteristics of the high-enthalpy geothermal reservoirs. Conceptual model of the Sabalan geothermal field is provided through integrating the various exploring information including the structural data, geological data, geophysical models, well logs and field evidences. Heat source is properly estimated by implementing the Curie depth map. The finite element method, adapted to the complex geometry of the model, is used to solve the governing equations. All-important physical and structural properties of the reservoir including the anisotropic and heterogonous permeability distribution, fluid flow through the faults and specific boundary conditions are considered. Optimization analysis is conducted to calibrate the model parameters. Simulated thermodynamic properties of the reservoir are compared with the wellbore measured data to validate the results.
Geophysical Prospecting
Ground-penetrating radar is one of the most effective methods of detecting shallow buried objects... more Ground-penetrating radar is one of the most effective methods of detecting shallow buried objects. Ground-penetrating radar radargram is a vertical map of the radar pulse reflections that returns from subsurface objects, and in the case of cylindrical objects, it would be a hyperbola. In order to get clear and accurate information on the presence, location, and geometry of the buried objects, the radargrams need to be interpreted. Interpretation of the results is a time-consuming task and needs an expert with vast knowledge. Development of an automatic interpretation method of B-scan ground-penetrating radar images would be an effective and efficient solution to this problem. A novel automatic interpretation method of ground-penetrating radar images, based on simultaneous perturbation artificial bee colony algorithm using tournament selection strategy, simultaneous perturbation stochastic approximation method, and new search equations, is introduced in this paper. The proposed algorithm is used to extract geometrical parameters, i.e. depth, location, and radius, of buried cylindrical objects in order to assess its accuracy. Synthetic data, simulated using GprMax2D forward modelling program, and real data, surveyed in the campus of Isfahan University of Technology, are used in the assessment. The performance of the proposed method in detecting synthetic hyperbolas is compared with that of the original artificial bee colony algorithm, genetic algorithm, and modified Hough transform. The results show superiority of the proposed algorithm, in detecting synthetic hyperbolas. Furthermore, the performance of the proposed method in estimating depth and radius of pipes in real ground-penetrating radar images is compared with that of the modified Hough transform. The results indicate higher accuracy of the proposed method in estimating geometrical parameters of the buried cylindrical objects.
Journal of Water and Soil Science
In addition to kinematic description of biological reaction, flow pattern plays an important role... more In addition to kinematic description of biological reaction, flow pattern plays an important role in designing constructed wetlands. This study investigates the effects of flow distribution on constructed sub-surface horizontal flow wetland with a length of 26 m, width of 4 m and 1% bed slope in order to understand internal hydraulic functioning patterns. Inlet configuration is selected as a variable parameter. Three different cases of inlet and outlet configurations were 1) midpoint, 2) corner, and 3) uniform. Outlet has been fixed in all configurations. Uranine tracer was used to determine the influences of flow distribution by drawing hydraulic retention time curve in different cases. Results showed that mean residence times for each configuration were equal to 4.53, 3.24 and 4.65 days, respectively. Retention time distribution curve provided conditions, not only for showing dispersion patterns throughout system but also for interpreting hydraulic parameters like hydraulic efficiency and effective volume. According to the retention time curve, effective volume was 87.5% in configurations 1 and 3, and 62.1% in configuration 2 following numerous shortcircuiting ratios. Finally, the best configuration of inlet-outlet layout to improve the performance of effluent treatment and use the geometry effectively was found to be the uniform-midpoint based on physical experiments followed by midpoint-midpoint as the second best.
Renewable Energy, 2016
This paper introduces a computational model for transient high enthalpy fluid flow through geothe... more This paper introduces a computational model for transient high enthalpy fluid flow through geothermal wellbores. The drift-flux model is utilized to formulate the physical behavior of fluid, and the constitutive relationships are described using relevant equations of state and empirical relationships. The governing equations are solved using the finite element method. All important physical phenomena and processes occurring along the wellbore, including buoyancy, phase change, compressibility, thermal interaction, wall friction and slip between phases are considered. Airlifting of water and air, initially existing in the wellbore before production, is also considered. During airlifting and early stages of production, two fluids exist along the wellbore: airlifted water-dry air fluid, and reservoir water-vapor fluid; giving rise to a discontinuity in thermodynamic properties between the two fluids. The discontinuity is modeled using the level-set method. Two numerical examples illustrating the computational capability and accuracy of the model are presented. The physical phenomena occurring during airlifting and production along the wellbore are highlighted.
Computational Methods, 2006
The modified Finite Point Method (FPM) is considered as one of the latest developments among the ... more The modified Finite Point Method (FPM) is considered as one of the latest developments among the meshless numerical methods. In order to achieve accurate results using modified FPM, it is essential to impose suitable mixed Boundary Conditions (BC) along with simultaneously satisfying both the governing Partial Differential Equation (PDE) at internal nodes and the associated BC at the nodes located