44 research outputs found
Cohomology and Deformations of left-symmetric Rinehart Algebras
No full textWe introduce a notion of left-symmetric Rinehart algebras, which is a generalization of a left-symmetric algebras. The left multiplication gives rise to a representation of the corresponding sub-adjacent Lie-Rinehart algebra. We construct left-symmetric Rinehart algebra from O-operators on Lie-Rinehart algebra. We extensively investigate representations of a left-symmetric Rinehart algebras. Moreover, we study deformations of left-symmetric Rinehart algebras, which is controlled by the second cohomology class in the deformation cohomology. We also give the relationships between O-operators and Nijenhuis operators on left-symmetric Rinehart algebras.arXiv admin note: text overlap with arXiv:1710.03749, arXiv:1312.6526, arXiv:1808.01909 by other author
Phenotypic and Molecular Assessment for Genetic Diversity of Egyptian Wheat Varieties
No full textGENETIC diversity among plant species is important for improving plant traits. Its estimation is very essential to help selection of genetic resources in breeding programs. Moreover, it is the base for effective and successful crop enhancement and can be assessed by several methods i.e. using morphological trait (resistance to leaf rust) and molecular markers. In this study, genetic diversity was assessed among the 53 tested wheat varieties using 15 leaf rust pathotypes under greenhouse condition at seedling stage. In addition, the genetic diversity was assessed also using 10 molecular markers (microsatellite markers) linked to rust resistant genes. The cluster analysis indicated three sub-clusters based on phenotypic and molecular data. In general, low level (r= 0.15) of correlation was obtained between the phenotypic and the genotypic data, however, the molecular analysis is more efficient for estimating genetic diversity. Molecular analysis is an effi cient method because it’s not affected by environment, fast, more accurate and doesn’t need earlier pedigree information which can improve the effi cacy of molecular breeding practices
Machine learning model optimization for compressional sonic log prediction using well logs in Shahd SE field, Western Desert, Egypt
No full textAbstract Compressional sonic logs is one of the important logs for subsurface characterization, reservoir evaluation, and wellbore stability analysis. However, acquiring these logs is often challenging due to logistical constraints. This study explores the application of machine learning (ML) techniques to predict compressional sonic logs using conventional well logs from five wells. The methodology involves data preprocessing, feature selection, and training various regression models, including Random Forest, CatBoost, XGBoost, K-Nearest Neighbors (KNN), Support Vector Machines (SVM), and Deep Neural Networks (DNN). Model performance is optimized through hyperparameter tuning and evaluated using correlation coefficients and root mean square error (RMSE) metrics. Results indicate that ensemble models (Random Forest, CatBoost, XGBoost) achieve the highest accuracy, with correlation coefficients ranging from 89 to 89.6% and RMSE between 5.85 and 6.03. Additionally, feature engineering and data cleaning significantly improve model performance, while input scaling is essential for SVM, KNN, and DNN models. Incorporating blind well testing further enhances reliability. This study presents a robust ML-based workflow for predicting compressional sonic logs, offering a cost-effective solution for reservoir management and geomechanical analysis
Delineation of the reservoir petrophysical parameters from well logs validated by the core samples case study Sitra field, Western Desert, Egypt
No full textAbstract In the northern section of the Western Desert, there are many extremely profitable petroleum and natural gas deposits in the Abu EL-Gharadig Basin. This study aims to highlight the hydrocarbon potential of Abu Roash F Formation, which stands for high organic content unconventional tight reservoirs, and Abu Roash G Formation which stands for conventional sand reservoirs, in Sitra field located in the central-western part of the Abu EL-Gharadig Basin. The research employed well-log data from four wells to ascertain petrophysical properties combined with core samples of two wells for a comprehensive examination and description of lithology. Initially, we commenced the execution of petrophysical analysis, encompassing log quality control procedures. Subsequently, we identified and revealed zones of interest and hydrocarbon indicators in both formations. Additionally, we ascertained the three most influential parameters, shale Volume, effective Porosity, and water saturation, which serve as defining factors for reservoir quality. Subsequently, an examination of the core samples, which encompassed lithologic description, lithofacies analysis, paleoenvironmental interpretation, petrographic analysis, and porosity assessment is conducted. For the sake of a more accurate interpretation, we conclude our research with cartographic maps created to evaluate the geographical distribution of hydrocarbon potential based on petrophysical characteristics, Distribution of the net-to-gross ratio among wells by correlating the litho-saturation models (rock models) for the four wells. The foregoing results declare that The Abu Roash F carbonate-rich rocks are a contender for unconventional tight oil reservoir potential with thin secondary porosity and high organic content, which normally requires a kind of hydraulic fracturing for prospective oil extraction, Furthermore, the upper section of Abu Roash G formation, particularly in well sitra8-03, has highly favorable conventional reservoir characteristics
Role of Seismic Refraction Tomography (SRT) in bedrock mapping; case study from industrial zone, Ain-Sokhna area, Egypt
No full textIn this study, eighteen compressional P-wave seismic refraction profiles survey was conducted on the western side of the Gulf of Suez, Egypt, to map bedrock topography, which is vital information in foundation pole placement and design for large factory construction. The configuration of the seismic survey consists of 10 metres geophone intervals (12 and 24 channels) with a total survey length of 3150 metres survey length. The seismic compressional wave velocity distribution reveals three layers ranging from (400 to 1100 m/s), (1200 to 2000 m/s), and (2200 to 3500 m/s). According to the data, the first low-velocity layer represents unconsolidated Wadi sediments. The second layer, on the other hand, comprises consolidated Wadi sediments, while the third layer comprises fractured to intact sandstone bedrock. The thickness of the first layer is believed to be between 0.5 and 10 m, while the thickness of the second layer is between 8.5 and 25 m. Pseudo-3D model of velocity distribution was constructed, revealing the presence of several low-velocity zones at a depth ranging from 15 to 32 m. Then, the topography of the non-rippable sandstone rock mass was mapped utilizing 3-D model. Finally, the correlation between seismic refraction tomography (SRT) results and nearby well logging dataset drilled by the Egyptian Geological Survey and Mining Authority (EGSMA) matched quite well. It may be inferred that, up to a depth of 15 to 32 metres, there is a high-velocity rock layer suitable for constructing deep foundations for multiple levels of the mega factory
Pre-stack seismic inversion for reservoir characterization in Pleistocene to Pliocene channels, Baltim gas field, Nile Delta, Egypt
No full textAbstract The Nile Delta, North Africa’s leading gas-producing region, was the focus of this study aimed at delineating gas-bearing sandstone reservoirs from the Pleistocene to Pliocene formations using a combination of pre-stack inversion and rock physics analysis. This research employed seismic inversion techniques, including full-angle stack seismic volumes, well logs, and 3-D with rock physics modeling to refine volumes of P-wave velocity (Vp), S-wave velocity (Vs), and density. Traditional seismic attributes, such as far amplitude, proved insufficient for confirming gas presence, highlighting partial angle stacks, integrated the need for advanced methods. Extended Elastic Impedance (EEI) analysis was used to predict fluids and identify lithology in clastic reservoir environments. The EEI approach facilitated the determination of optimal projection angles for key petrophysical properties such as porosity, shale volume, and water saturation. This method was applied to the middle Pliocene (Kafr El Sheikh Formation) and the Pleistocene (El Wastani Formation), revealing promising drilling sites. In the Kafr El Sheikh Formation, porosity ranged from 16 to 29%, shale volume from 21 to 40%, and hydrocarbon saturation from 25 to 90%. The study concludes that integrating pre-stack seismic inversion with EEI significantly enhances the likelihood of identifying gas-bearing sands while reducing exploration risks. The improved POS for the Pleistocene anomaly gas bearing sand (from 49 to 69%) and the middle Pliocene anomaly (from 46 to 66%) underscores the effectiveness of this approach in the Baltim Field, Offshore Nile Delta, and supports further drilling and development wells
Petrophysical assessment of the Hammam Faraun, Matulla and Nubia Reservoirs in the Ashrafi Oil Field, Gulf of Suez
No full textAbstract The Hammam Faraun, Matulla, and Nubia formations in the Ashrafi oil field, in the southern Gulf of Suez, Egypt, are key hydrocarbon reservoirs with significant economic importance. These formations, characterized by their favorable reservoir properties and structural settings, play a crucial role in oil and gas accumulation. Their study provides valuable insights into regional petroleum systems and guides exploration and production activities. The Ashrafi Oil Field is one of the most complex and important areas due to its intricate geological framework, which closely resembles that of the Red Sea. Its proximity to the Red Sea further emphasizes its significance. Therefore, the findings from this study can serve as a valuable analogy for understanding the geology of the Red Sea. This study presents a comprehensive structural interpretation and petrophysical evaluation of the Hammam Faraun, Matulla, and Nubia formations by examining well log data and seismic lines, the research quantifies essential petrophysical parameters that characterize the reservoir properties and hydrocarbon potential of these formations. The Hammam Faraun Member exhibits effective porosity values ranging from 0.15 to 0.25 and water saturation levels between 0.23 and 0.67, indicating a significant capacity for hydrocarbon storage, especially in the northern region where net pay thickness can reach up to 60 ft. The Matulla Formation shows effective porosity values between 0.10 and 0.20, with water saturation levels ranging from 0.31 to 0.41 and net pay thickness varying from 51 to 269 ft, highlighting its substantial hydrocarbon reserves. In contrast, the Nubia Formation, characterized by its uniform sandstone composition, has an effective porosity of approximately 0.18 and a consistent water saturation level of about 0.24, with net pay thicknesses between 72 and 155 ft, marking it as an important target for hydrocarbon exploration. Also, the resulting structural interpretation reveals a series of normal faulted structures, including horsts, half-grabens, and step faults. These faults extend across the area, primarily trending northeast-southwest (clysmic trend), with minor northwest-southeast faults perpendicular to the major faults, creating a complex fault network. Integrating this structures with petrophysical parameters such as shale volume, effective porosity, and hydrocarbon saturation provides critical insights into reservoir quality, informing future exploration and production strategies. The study further underscores the lateral variations in water saturation and net pay thickness across the formations, which are closely linked to facies changes. This thorough analysis enhances our understanding of the geological framework and serves as a vital resource for optimizing hydrocarbon recovery and guiding exploration initiatives in the Ashrafi Oil Field. The findings underline the potential of these formations as significant contributors to the region’s hydrocarbon resources, emphasizing the necessity for ongoing exploration and development efforts. Additionally, the insights gained from this research can facilitate the implementation of advanced recovery techniques, ensuring the efficient utilization of hydrocarbon resources while addressing the challenges associated with reservoir management in the Gulf of Suez region and the Red sea
Three dimensional analysis of unanticipated behavior of a deep excavation
No full textA three-dimensional (3D) effective stress finite element analysis, modified to account for hydrofracturing and gassy soil behavior, is used to examine the potential for the venting of water and gas from a bedrock aquifer and through 13–14 m of low permeability clayey silt between the base of the excavation and the bedrock following excavation to about 24 m in an approximately 40 m thick clayey silt deposit. The clayey deposit contained sand lenses with dissolved gas. The analysis predicts that the exsolution of this dissolved gas, caused by a reduction in total stress due to the excavation, results in liquefaction of the sand in the lenses and consequent lateral deformations of the side slopes. The analysis predicts hydrofracturing through the remaining clayey silt when the excavation reaches its final depth and this explains the venting of water and gas from the underlying aquifer that was observed above a local bedrock high. The presence of gassy sand lenses created weak zones within the clayey deposit that influenced the path of the hydrofracturing. However, the analyses suggest that, for the depth of excavation and bedrock elevation examined, hydrofracturing and subsequent venting would have occurred even if there had been no sand lenses.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
