Mohamed Eleraki - Academia.edu (original) (raw)
Uploads
Conference Presentations by Mohamed Eleraki
A large quantity of wastewater is collected in three oxidation ponds raising serious environmenta... more A large quantity of wastewater is collected in three oxidation ponds raising serious environmental concern in
the east of Tenth of Ramadan city, Egypt. In the present work, the DC resistivity method in the form of 1D and 2D was
applied for wastewater percolation monitoring in the area around the oxidation ponds. The resistivity measurements were
integrated with laboratory studies of soil samples to estimate grain size, porosity, clay contents and degree of saturation.
According to the former Schlumberge sounding survey, six 2D resistivity profiles were measured closed to the ponds.
Wenner beta and Pole-dipole electrode arrays were selected for 2D resistivity imaging based on a prior synthetic modelling.
The 1D model generation and verification by the use of genetic algorithms (GA) represent an accurate quick solution to the
subsurface resistivity layer distributions. A conventional derivative-based inversion with cell-model provides valuable
constraints to interpret the 2D resistivity measurements. The inversion results demonstrate a decreasing in resistivity values
around the ponds indicating a percolation of wastewater to 15 m maximum depth. Expanding zones of decreasing soil
resistivity immedialely around the oxidation ponds reflect that the method is useful for assessing the oxidation ponds impact.
Soil parameters derived from laboratory measurements were very valuable for quantitative evaluation of the geophysical
interpretation.
Papers by Mohamed Eleraki
Petroleum, 2020
Formation damage due to fines migration is a major reason for well productivity decline for oil a... more Formation damage due to fines migration is a major reason for well productivity decline for oil and gas wells. Formation fines are small enough to pass through pore throats causing pore plugging and permeability decline. Different factors affect fines migration such as flow rate, salinity, pH value, reservoir temperature and oil polarity, as well as changes in chemical environment induced by Enhanced Oil Recovery (EOR) agents. This paper focused on the effect of flow rates on fines detachment from the grain surfaces, which causing permeability reduction. As the fluid inside the reservoir moves towards the wellbore, the fluid velocity increases, when the fluid reaches the critical flow rate these fines can be picked up into the fluid. These fines captured by thinner pore throats causing pore plugging and permeability reduction. Different concentrations of nanoparticles were used to fix these fines on their sources and prevent their mobilization at high flow rates. The unique techniqu...
A quantity of mineral occurrences are hosted by hydrothermally altered rocks and, consequently, t... more A quantity of mineral occurrences are hosted by hydrothermally altered rocks and, consequently, the discriminations of mineralized sectors are considerable in mineral exploration studies. Moreover, hydrothermal zones in deformed bedrock are usually controlled by structural and/or tectonic features. However, the hydrothermal zones mapping in mafic/ultramafic rocks is, generally, a challenge using an individual geophysical method due to chemical and mineralogical changes through the deformation zone. As a tectonically active area, the regional geological mapping indicates the occurrence of many mineralized and hydrothermally altered zones at Gabal El-Rubshi, CED, Egypt. Accordingly, our study focuses on a sequential use of high resolution geophysical data for characterizing the hydrothermal zones. According to airborne magnetic data, the images represents magnetic signature of hydrothermal zones in mafic/ultramafic rocks associated with structural evidences. Besides, airborne spectrom...
Space Weather
In this work, we propose an artificial neural network (ANN) with seven input parameters for the p... more In this work, we propose an artificial neural network (ANN) with seven input parameters for the prediction of disturbance storm time (Dst) index 1 to 12 hr ahead. The ANN uses past near-Earth solar wind parameter values to forecast the Dst. The input parameters are the solar wind interplanetary magnetic field, north-south component of interplanetary magnetic field, temperature, density, speed, pressure, and electric field. The ANN was trained on the data period from 1 January 2007 to 31 December 2015, which contains 78,888 hourly data samples. While the period from 1 January 2016 to 31 May 2017 was used to test the prediction capabilities of the ANN. Several ANN structures were tested and the best results were determined using the correlation coefficient (R) during the training and prediction phases. The results indicate an adequate accuracy of R = 0.876 for prediction 2 hr in advance and R = 0.857 for prediction 12 hr in advance. The power of the proposed ANN was illustrated using the strongest six storms recorded during the prediction period. Generally, the duration and number of the input parameters significantly affect the training and prediction performance of the applied ANN. The results are outstanding in term of accuracy when considering a medium-term prediction of 12 hr in advance and in terms of timing of the Dst minimum occurrence. In addition, the results show a strong dependence on the solar wind electric current. Plain Language Summary We propose an artificial neural network for the prediction of disturbance storm time (Dst) index 1 to 12 hr ahead. The ANN uses 24 past hourly solar wind parameters values to forecast the Dst index. The input parameters are the solar wind interplanetary magnetic field, southward component of interplanetary magnetic field, temperature, density, speed, pressure, and electric field. Several ANN structures were tested and the best results were determined using the correlation coefficient (R) during the training and prediction phases. The results indicate an adequate accuracy of R = 0.876 for prediction 2 hr in advance and R = 0.857 for prediction 12 hr in advance. Generally, the duration and number of the input parameters significantly affect the training and prediction performance of the applied ANN. The results are outstanding in term of accuracy when considering a medium-term prediction of 12 hr in advance and in term of timing of the Dst minimum occurrence. In addition, the results show a strong dependence on the solar wind electric current.
Natural Hazards and Earth System Sciences Discussions, 2015
In this contribution, we developed an extended stochastic technique for seismic hazard assessment... more In this contribution, we developed an extended stochastic technique for seismic hazard assessment purposes. This technique depends on the hypothesis of stochastic technique of Boore (2003) "Simulation of ground motion using the stochastic method. Appl. Geophy. 160:635–676". The essential characteristics of extended stochastic technique are to obtain and simulate ground motion in order to minimize future earthquake consequences. The first step of this technique is defining the seismic sources which mostly affect the study area. Then, the maximum expected magnitude is defined for each of these seismic sources. It is followed by estimating the ground motion using an empirical attenuation relationship. Finally, the site amplification is implemented in calculating the peak ground acceleration (PGA) at each site of interest. We tested and applied this developed technique at Cairo, Suez, Port Said, Ismailia, Zagazig and Damietta cities to predict the ground motion. Also, it is ap...
Quarterly Journal of Engineering Geology and Hydrogeology, 2010
Environmental Earth Sciences, 2016
To understand the impact of sea level rise (SLR) and aquifer intensive use would cause to the gro... more To understand the impact of sea level rise (SLR) and aquifer intensive use would cause to the groundwater level and saltwater intrusion, an integrated relationship between salinity and electrical resistivity of a Quaternary aquifer is established in the northern part of East Nile Delta (El Sharkia area), Egypt. Historical data of groundwater salinity are mapped and compared with the current water samples to better understand the salinity spatial variability. The salinity maps show that salinization has increased sustainably. Additionally, the transition/dynamic zone related to SLR and/or excessive pumping can be addressed. In particular, the surface DC resistivity soundings were carried out to demonstrate the vertical and horizontal salinity distributions in the area. In the course of this study, the 1D model generation using a hybrid genetic algorithm (GA) was applied and tested using borehole information. The constructed geoeletrical cross-sections emphasize and delineate the extension of saltwater intrusion. Cleary, it is found that due to excessive pumping from shallow wells over the last decades, the subsurface resistivity and TDS vertical distributions can change rapidly within a short distance. Additionally, the results show that despite the dominance of brackish and saltwater at the northern part of the area, perched low conductive lenses are observed reflecting a low level of groundwater salinization. To obtain a link between water salinity and aquifer resistivity, an empirical relationship was derived to predict the salinity variations at different depths. In comparison with the measured total dissolved solids (TDS), the predicted salinity map appears realistic. These results demonstrate the important role of the integration between resistivity and salinity measurements for mapping the groundwater salinization with depth, and call for further research to plan and manage the area's water resources.
Advances in Natural and Applied Sciences
The majority of the current 1D geophysical inversion approaches depends on the direct and iterati... more The majority of the current 1D geophysical inversion approaches depends on the direct and iterative interpretation methods. Because these approaches have a degree of nonuniqueness and they will succeed only if an initial model already close to the best solution is available, the genetic algorithm (GA) approach is applied in this paper for optimal interpretation of the measured direct current (DC) resistivity data. In the present work, Tenth of Ramadan city was considered as a case study for application of GA to study the soil characterization using resistivity measurements. Thirty six vertical electrical soundings (VESs) were measured for characterizing the subsurface soils to a depth of about 25 m. The reliability of the results with application of GA approach is checked by comparing the inversion results with lithologic and borehole information. The 1D model generation using a GA represents an accurate and quick solution to image the subsurface resistivity distributions; the large number of forward calculations in GA increases the chance of acquiring the best model correspondence to the actual geological situation. The intrinsic resistivity values are presented in the form of maps, cross-sections and 3D visualized model to indicate the nature of the heterogeneity of the shallow subsurface. Interpretation of DC resistivity data demonstrates existence of near surface sandy clay barrier layer, affecting the development plan of this important urban community. A trend of decreasing resistivity is observed around oxidation ponds, indicating a wastewater percolation around such ponds. In addition, the heterogeneity of the shallow subsurface can be considered as the main reason of the fluid infiltration. These reliable results are, therefore, considered a key for further geophysical prospecting in monitoring the environmental impact of oxidation ponds and the near surface sandy clay layer.
NRIAG Journal of Astronomy and Geophysics, 2014
The long period Pc5 pulsations (1.7-6.7 mHz) have been observed at Misallat observatory during th... more The long period Pc5 pulsations (1.7-6.7 mHz) have been observed at Misallat observatory during the period 01/Jul/2011 to 30/Jun/2012. The study correlates the Pc5 intensity during day and night times. We present a case study of Pc5 pulsation observed in the 08-12 UT time intervals during the initial phase of the magnetic storm of October 5th, 2011. We use data from Misallat and Abu-Simple magnetic observatories in Egypt and other four observatories (Addis Ababa, Tamanrasset, L'Aquila and Belsk) belonging to the INTERMAGNET network. We propose that the source of this pulsation is identified as compressional waves caused by fluctuations of the solar wind dynamic pressure.
A large quantity of wastewater is collected in three oxidation ponds raising serious environmenta... more A large quantity of wastewater is collected in three oxidation ponds raising serious environmental concern in
the east of Tenth of Ramadan city, Egypt. In the present work, the DC resistivity method in the form of 1D and 2D was
applied for wastewater percolation monitoring in the area around the oxidation ponds. The resistivity measurements were
integrated with laboratory studies of soil samples to estimate grain size, porosity, clay contents and degree of saturation.
According to the former Schlumberge sounding survey, six 2D resistivity profiles were measured closed to the ponds.
Wenner beta and Pole-dipole electrode arrays were selected for 2D resistivity imaging based on a prior synthetic modelling.
The 1D model generation and verification by the use of genetic algorithms (GA) represent an accurate quick solution to the
subsurface resistivity layer distributions. A conventional derivative-based inversion with cell-model provides valuable
constraints to interpret the 2D resistivity measurements. The inversion results demonstrate a decreasing in resistivity values
around the ponds indicating a percolation of wastewater to 15 m maximum depth. Expanding zones of decreasing soil
resistivity immedialely around the oxidation ponds reflect that the method is useful for assessing the oxidation ponds impact.
Soil parameters derived from laboratory measurements were very valuable for quantitative evaluation of the geophysical
interpretation.
Petroleum, 2020
Formation damage due to fines migration is a major reason for well productivity decline for oil a... more Formation damage due to fines migration is a major reason for well productivity decline for oil and gas wells. Formation fines are small enough to pass through pore throats causing pore plugging and permeability decline. Different factors affect fines migration such as flow rate, salinity, pH value, reservoir temperature and oil polarity, as well as changes in chemical environment induced by Enhanced Oil Recovery (EOR) agents. This paper focused on the effect of flow rates on fines detachment from the grain surfaces, which causing permeability reduction. As the fluid inside the reservoir moves towards the wellbore, the fluid velocity increases, when the fluid reaches the critical flow rate these fines can be picked up into the fluid. These fines captured by thinner pore throats causing pore plugging and permeability reduction. Different concentrations of nanoparticles were used to fix these fines on their sources and prevent their mobilization at high flow rates. The unique techniqu...
A quantity of mineral occurrences are hosted by hydrothermally altered rocks and, consequently, t... more A quantity of mineral occurrences are hosted by hydrothermally altered rocks and, consequently, the discriminations of mineralized sectors are considerable in mineral exploration studies. Moreover, hydrothermal zones in deformed bedrock are usually controlled by structural and/or tectonic features. However, the hydrothermal zones mapping in mafic/ultramafic rocks is, generally, a challenge using an individual geophysical method due to chemical and mineralogical changes through the deformation zone. As a tectonically active area, the regional geological mapping indicates the occurrence of many mineralized and hydrothermally altered zones at Gabal El-Rubshi, CED, Egypt. Accordingly, our study focuses on a sequential use of high resolution geophysical data for characterizing the hydrothermal zones. According to airborne magnetic data, the images represents magnetic signature of hydrothermal zones in mafic/ultramafic rocks associated with structural evidences. Besides, airborne spectrom...
Space Weather
In this work, we propose an artificial neural network (ANN) with seven input parameters for the p... more In this work, we propose an artificial neural network (ANN) with seven input parameters for the prediction of disturbance storm time (Dst) index 1 to 12 hr ahead. The ANN uses past near-Earth solar wind parameter values to forecast the Dst. The input parameters are the solar wind interplanetary magnetic field, north-south component of interplanetary magnetic field, temperature, density, speed, pressure, and electric field. The ANN was trained on the data period from 1 January 2007 to 31 December 2015, which contains 78,888 hourly data samples. While the period from 1 January 2016 to 31 May 2017 was used to test the prediction capabilities of the ANN. Several ANN structures were tested and the best results were determined using the correlation coefficient (R) during the training and prediction phases. The results indicate an adequate accuracy of R = 0.876 for prediction 2 hr in advance and R = 0.857 for prediction 12 hr in advance. The power of the proposed ANN was illustrated using the strongest six storms recorded during the prediction period. Generally, the duration and number of the input parameters significantly affect the training and prediction performance of the applied ANN. The results are outstanding in term of accuracy when considering a medium-term prediction of 12 hr in advance and in terms of timing of the Dst minimum occurrence. In addition, the results show a strong dependence on the solar wind electric current. Plain Language Summary We propose an artificial neural network for the prediction of disturbance storm time (Dst) index 1 to 12 hr ahead. The ANN uses 24 past hourly solar wind parameters values to forecast the Dst index. The input parameters are the solar wind interplanetary magnetic field, southward component of interplanetary magnetic field, temperature, density, speed, pressure, and electric field. Several ANN structures were tested and the best results were determined using the correlation coefficient (R) during the training and prediction phases. The results indicate an adequate accuracy of R = 0.876 for prediction 2 hr in advance and R = 0.857 for prediction 12 hr in advance. Generally, the duration and number of the input parameters significantly affect the training and prediction performance of the applied ANN. The results are outstanding in term of accuracy when considering a medium-term prediction of 12 hr in advance and in term of timing of the Dst minimum occurrence. In addition, the results show a strong dependence on the solar wind electric current.
Natural Hazards and Earth System Sciences Discussions, 2015
In this contribution, we developed an extended stochastic technique for seismic hazard assessment... more In this contribution, we developed an extended stochastic technique for seismic hazard assessment purposes. This technique depends on the hypothesis of stochastic technique of Boore (2003) "Simulation of ground motion using the stochastic method. Appl. Geophy. 160:635–676". The essential characteristics of extended stochastic technique are to obtain and simulate ground motion in order to minimize future earthquake consequences. The first step of this technique is defining the seismic sources which mostly affect the study area. Then, the maximum expected magnitude is defined for each of these seismic sources. It is followed by estimating the ground motion using an empirical attenuation relationship. Finally, the site amplification is implemented in calculating the peak ground acceleration (PGA) at each site of interest. We tested and applied this developed technique at Cairo, Suez, Port Said, Ismailia, Zagazig and Damietta cities to predict the ground motion. Also, it is ap...
Quarterly Journal of Engineering Geology and Hydrogeology, 2010
Environmental Earth Sciences, 2016
To understand the impact of sea level rise (SLR) and aquifer intensive use would cause to the gro... more To understand the impact of sea level rise (SLR) and aquifer intensive use would cause to the groundwater level and saltwater intrusion, an integrated relationship between salinity and electrical resistivity of a Quaternary aquifer is established in the northern part of East Nile Delta (El Sharkia area), Egypt. Historical data of groundwater salinity are mapped and compared with the current water samples to better understand the salinity spatial variability. The salinity maps show that salinization has increased sustainably. Additionally, the transition/dynamic zone related to SLR and/or excessive pumping can be addressed. In particular, the surface DC resistivity soundings were carried out to demonstrate the vertical and horizontal salinity distributions in the area. In the course of this study, the 1D model generation using a hybrid genetic algorithm (GA) was applied and tested using borehole information. The constructed geoeletrical cross-sections emphasize and delineate the extension of saltwater intrusion. Cleary, it is found that due to excessive pumping from shallow wells over the last decades, the subsurface resistivity and TDS vertical distributions can change rapidly within a short distance. Additionally, the results show that despite the dominance of brackish and saltwater at the northern part of the area, perched low conductive lenses are observed reflecting a low level of groundwater salinization. To obtain a link between water salinity and aquifer resistivity, an empirical relationship was derived to predict the salinity variations at different depths. In comparison with the measured total dissolved solids (TDS), the predicted salinity map appears realistic. These results demonstrate the important role of the integration between resistivity and salinity measurements for mapping the groundwater salinization with depth, and call for further research to plan and manage the area's water resources.
Advances in Natural and Applied Sciences
The majority of the current 1D geophysical inversion approaches depends on the direct and iterati... more The majority of the current 1D geophysical inversion approaches depends on the direct and iterative interpretation methods. Because these approaches have a degree of nonuniqueness and they will succeed only if an initial model already close to the best solution is available, the genetic algorithm (GA) approach is applied in this paper for optimal interpretation of the measured direct current (DC) resistivity data. In the present work, Tenth of Ramadan city was considered as a case study for application of GA to study the soil characterization using resistivity measurements. Thirty six vertical electrical soundings (VESs) were measured for characterizing the subsurface soils to a depth of about 25 m. The reliability of the results with application of GA approach is checked by comparing the inversion results with lithologic and borehole information. The 1D model generation using a GA represents an accurate and quick solution to image the subsurface resistivity distributions; the large number of forward calculations in GA increases the chance of acquiring the best model correspondence to the actual geological situation. The intrinsic resistivity values are presented in the form of maps, cross-sections and 3D visualized model to indicate the nature of the heterogeneity of the shallow subsurface. Interpretation of DC resistivity data demonstrates existence of near surface sandy clay barrier layer, affecting the development plan of this important urban community. A trend of decreasing resistivity is observed around oxidation ponds, indicating a wastewater percolation around such ponds. In addition, the heterogeneity of the shallow subsurface can be considered as the main reason of the fluid infiltration. These reliable results are, therefore, considered a key for further geophysical prospecting in monitoring the environmental impact of oxidation ponds and the near surface sandy clay layer.
NRIAG Journal of Astronomy and Geophysics, 2014
The long period Pc5 pulsations (1.7-6.7 mHz) have been observed at Misallat observatory during th... more The long period Pc5 pulsations (1.7-6.7 mHz) have been observed at Misallat observatory during the period 01/Jul/2011 to 30/Jun/2012. The study correlates the Pc5 intensity during day and night times. We present a case study of Pc5 pulsation observed in the 08-12 UT time intervals during the initial phase of the magnetic storm of October 5th, 2011. We use data from Misallat and Abu-Simple magnetic observatories in Egypt and other four observatories (Addis Ababa, Tamanrasset, L'Aquila and Belsk) belonging to the INTERMAGNET network. We propose that the source of this pulsation is identified as compressional waves caused by fluctuations of the solar wind dynamic pressure.