Southwestern Desert Research Articles

Ethane integration project—a study for Egyptian NGLs plants and their economics

For Egypt, ethane is a vital chemical precursor, with the potential to significantly attract financial resources and drive economic growth. Enhancing its added value necessitates efficient recovery of ethane before it enters the national grid without processing. This research investigates the technical and economic feasibility of integrating natural gas liquids (NGLs) from three Egyptian NGLs plants—South Western Desert NGLs (SWD NGLs), North Western Desert NGLs (NWD NGLs), and East Mediterranean NGLs (EMD NGLs)—to improve ethane recovery from natural gas fields. The study focuses on revamping these NGLs plants using various NGLs recovery techniques, conducting a comprehensive comparison to identify the most effective methods for processing rich feed gas. Detailed design of the NGLs recovery processes was developed using HYSYS V.14 simulation software and supplementary calculation sheets. The design criteria encompass both technical and economic parameters to ensure a holistic approach in meeting project requirements. Results indicate a significant increase in ethane recovery: 16% for SWD NGLs, 10% for NWD NGLs (A, B, C), and 85% for EMD NGLs. This improvement will boost ethane feedstock for petrochemical companies from 2000 ton/day to 3500 ton/day, enabling increased polyethylene production. Economic analysis for the base case shows an expected internal rate of return (IRR) of 26%, a net present value (NPV) of USD 73 million, and a payback period of approximately 3 years. Sensitivity analysis on product prices, feed gas prices, and total capital investment confirms the project’s economic viability, with all cases showing feasibility (IRR ≥ 15%) except when product prices fall below USD 225/ton for propane, USD 215/ton for liquefied petroleum gas (LPG), and USD 25/bbl for condensate. This study highlights the potential for enhanced ethane recovery, offering substantial economic benefits and supporting the growth of Egypt’s petrochemical industry.

Depositional environments of Danian/Selandian of Kurkur Formation, Kurkur Oasis, south Western Desert, Egypt

In order to document the depositional environments of the Kurkur Formation in Southwestern Desert, Egypt, four surface sections measured in this region from north to south as follows: Gebel Garra, Wadi Abu-Sayal, Kurkur Oasis, and Sinn El-Kaddab. Planktonic foraminifera indicate that the age of Kurkur Formation in the study area is Danian to Selandian. Microfacies analysis shows graduation from wackestones, floatstones, and packstones in the lower part to oolitic and bioclastic grainstones in the upper section. The lower part of Kurkur Formation characterized by calcareous foraminifera assemblages, whereas arenaceous types are concentrated toward the uppermost part. Bivalves, gastropods, and echinoids are the most abundant macrofossils. Using the microfacies analyses and fossil content, the Kurkur Formation in the studied area deposited in middle neritic zone for the lower part, which is synchronous with the beginning of the Cenozoic transgression in the study area, and changed upward to inner neritic and supratidal environments.

Towards an understanding of hunting equipment used by early Holocene foragers of the Egyptian Southwestern Desert: Triangles of the El-Ghorab Unit

One of the Early Holocene archaeological cultures distinguished in the Egyptian Western Desert is defined as the El Ghorab Unit, and is dated to the 10th millennium cal BP. These hunter-gatherer groups lived on the shores of seasonal lakes (playas) and wetlands typical for the Early and Middle Holocene landscape of that part of the Saharan North Africa. They manufactured characteristic lithic artifact assemblages that have not been studied, so far, from a microwear perspective. The El Ghorab Unit lithic artifact assemblages are dominated by morphologically distinct triangular microliths, ca. 30–40 mm long and made from relatively wide blades, ca. 10 mm in width.This paper presents the results of morphological and functional analyses of El-Ghorab triangles from site E-16-03 located in the Gebel Ramlah/Nabta Playa region. At this locality, remnants of a few activity areas have been recorded on the northwestern margin of the Gebel Ramlah paleo-lake basin. The site consists of lithic artifact concentrations scattered around burned-earth hearth features (fireplaces). The function of the triangles is examined and interpreted here by also taking into account the specific paleoenvironmental and paleozoological record from site E-16-03.The El-Ghorab area of the Gebel Ramlah basin at E-16-03 contains three seasonally-specific, short-term hunting camps where hunting equipment was repaired and hunted game was brought to the site during spring time. Triangles were the main goal of lithic production. In the course of this research it has become evident that triangular microliths were mounted in hafts in different ways. This observation can be used as supporting evidence to conclude that various prehistoric human groups visited the Gebel Ramlah area during several seasonal cycles.

Recharge Sources and Hydrogeochemical Evolution of the groundwater in the Quaternary Aquifer El Gallaba Plain, Southwestern Desert, Egypt

Recharge Sources and Hydrogeochemical Evolution of the groundwater in the Quaternary Aquifer El Gallaba Plain, Southwestern Desert, Egypt

Inverting Gravity Data to Density and Velocity Models for Selected Area in Southwestern Iraq

The gravity method is a measurement of relatively noticeable variations in the Earth’s gravitational field caused by lateral variations in rock's density. In the current research, a new technique is applied on the previous Bouguer map of gravity surveys (conducted from 1940–1950) of the last century, by selecting certain areas in the South-Western desert of Iraqi-territory within the provinces' administrative boundary of Najaf and Anbar. Depending on the theory of gravity inversion where gravity values could be reflected to density-contrast variations with the depths; so, gravity data inversion can be utilized to calculate the models of density and velocity from four selected depth-slices 9.63 Km, 1.1 Km, 0.682 Km and 0.407 Km. The depths were selected using the power spectrum analysis technique of gravity data. Gravity data are inverted based on gravitational anomalies for each depth slice or level and the extracted equivalent depth data from available wells using a connection curve between densities and velocities, which were mostly compatible with Nafe and Drake's standard curve. The inverted gravity data images highlight the behavior of anomalies/structures in the model and domain of density/velocity, which can be utilized in the processing of the recorded seismic data and time to depth conversion, in parallel with available well's data information within the intended study area of South-Western Iraq.

Developing Spatial Models of Groundwater Quality in the Southwestern Desert of Iraq Using GIS, Inverse Distance Weighting, and Kriging Interpolation Techniques

Developing Spatial Models of Groundwater Quality in the Southwestern Desert of Iraq Using GIS, Inverse Distance Weighting, and Kriging Interpolation Techniques

Geothermal Gradients Inside Water Wells of East Oweinat Area, South Western Desert of Egypt

The regional geothermal pattern of Egypt has been previously defined from bottom hole temperature data inside oil wells in Northern Egypt and Gulf of Suez. For the same objective, geothermal gradient/heat flow determinations have also been conducted inside existing mineral exploration and water wells in Eastern Egypt and in Kharga Oasis in Western Desert as well as inside specially drilled regional gradient shallow boreholes in Eastern Egypt. To complement the regional geothermal picture in the southern part of Egypt, temperatures were measured inside seven water wells in a remote area in the south Western Desert at East Oweinat. The average calculated temperature gradient was found to amount to 12 mK/m, a value similar to that obtained from bottom hole temperature/depth relationship of deep artesian wells at Dakhla Oasis 300 km to the north, but much less than the normal gradient amounting to 20 mK/m in Northern Egypt. The data obtained emphasize the extension of the low heat flow province of the Mediterranean north of Egypt to its southern border with Sudan. A distribuição regional de fluxo geotérmico no Egito foi previamente definida a partir de temperaturas de fundo de poço medidas em poços de petróleo no norte do Egito e no golfo de Suez. Com o mesmo objetivo, determinações de gradientes térmicos e de fluxo de calor foram realizadas em poços para exploração mineral e de água no leste do Egito e no oásis de Kharga no deserto ocidental, assim como em poços rasos especialmente perfurados no leste do Egito. Para complementar a representação do fluxo térmico regional na parte sul do Egito, foram medidas temperaturas em sete poços de água em uma área remota no deserto do sudoeste em East Oweinat. O gradiente térmico médio encontrado é de 12 mk/m, valor similar ao obtido a partir de relações de temperatura de fundo de poço/profundidade de poços profundos no oásis de Dakhla 300 quilômetros mais ao norte, mas muito inferior ao gradiente geotérmico normal de 20 mk/m encontrado no norte do Egito. Os dados obtidos enfatizam a extensão da província de baixo fluxo térmico do norte mediterrâneo do Egito para a sua fronteira sul com o Sudão.

Noise Reduction of Aeromagnetic Data Using Artificial Neural Network

The high-frequency content of high-resolution aeromagnetic data is of particular interest to geophysic ists to identify mineral deposits, shallow faults, and dikes. However, high-resolution aeromagnetic data is contaminated by cultural noise generated from aircraft and man-made features. The culture noise must be removed before starting the interpretation process. Manual techniques are more selective of the noise; however slower and more expensive because they require considerable hands-on interaction. The present study develops a novel method for detecting and removing the culture noise from aeromagnetic data based on an artificial neural network (ANN) in an automatic way and comparing the results with a conventional algorithm using the nonlinear filter. The proposed method is tested using a theoretical example that combine a magnetic anomaly due to a dyke with three sources of cultural noise, besides using a practical example to increase the number of training pattern. The network is trained based on the backpropagation training function, where the algorithm updates the weight and bias states as per the Levenberg–Marquardt optimization. The optimization is reached during the training and validation process after 3,000 iterations. The correlation coefficient ( R) is utilized along with the mean squared error (MSE) as performance indices of the ANN. The ANN demonstrates the capability to detect the spiky data based on the optimal weights, thus allowing for removing and replacing them with clean data using the piecewise cubic Hermite interpolating polynomial (PCHIP) function. The practical utility of the two-method is discussed using high-resolution aeromagnetic data from the Tushka area located in the southwestern desert of Egypt. Comparing the denoising results using the two methods shows that the current approach is more effective in processing and more closely recovering the original magnetic data.

The First Side-Necked Turtle (Pleurodira, Bothremydidae) from the Campanian (Late Cretaceous) of Egypt

The Quseir Formation is an Upper Cretaceous (Campanian) deposit in the Kharga oasis of the Southwestern Desert (Egypt). This formation comprises a clastic sequence of bioturbated mudstone and sandstone intercalations, including rare scattered and fragmented vertebrate remains such as shark teeth, dinosaur remains, and turtle plates. These deposits indicate a supratidal marsh environment. A complete shell of a turtle discovered from the Quseir Formation, at the Kharga oasis, is attributed here to Bothremydini (Pleurodira, Bothremydidae), and determined as a new taxon: Khargachelys caironensis gen. et sp. nov. This form represents the only Bothremydini member currently identified in the Campanian record not only of Egypt but also of North Africa. Therefore, it helps fill the missing evolutionary gap from the Late Cretaceous pleurodires in Egypt and in North Africa.

An Integrated Approach to Unravel the Structural Controls on Groundwater Potentialities in Hyper-arid Regions Using Satellite and Land-Based Geophysics: A Case Study in Southwestern Desert of Egypt

An Integrated Approach to Unravel the Structural Controls on Groundwater Potentialities in Hyper-arid Regions Using Satellite and Land-Based Geophysics: A Case Study in Southwestern Desert of Egypt

Evaluating and projecting of climate extremes using a variable-resolution global climate model (VR-CESM)

Increasing risk of many natural hazards including floods, wildfires, and reduction of agricultural production are often due to extreme climate events such as heavy precipitation, heat waves and drought. In this study, the variable-resolution Community Earth system model (VR-CESM) was used to investigate potential changes in extreme climate events at refined-resolution (14 km) in the western U.S. and eastern China. The model performance for simulating climate extremes is evaluated by various extreme metrics and assessed against the PRISM reference dataset in the U.S. VR-CESM is also compared with other models at different resolutions, including the uniform coarser resolution model CESM with the same physical parameterization, and HadGEM2-WRF, one RCM in the CORDEX-NA ensembles with the same SST forcing as the GCMs. Among those precipitation extreme metrics, VR-CESM simulates the short-term daily metrics (e.g., 95th percentile precipitation) in the western U.S. well (with greater uncertainties in the Sierra Nevada and Cascade Mountains), but underestimates the long-term metrics (e.g., number of dry years) during the historical period. For temperature extremes, VR-CESM also overestimates the number of hot temperature extremes in California’s Central Valley and southwestern desert regions; this is consistent with the warm seasonal average JJA biases. In model intercomparisons, VR-CESM has smaller biases than CESM and HadGEM2-WRF for both extreme precipitation and temperature events. Additionally, the Palmer Drought Severity Index (PDSI) for all models is simulated at four watersheds and compared to the PRISM reference dataset with statistical testings for their similarities. Under RCP8.5 through 2050, VR-CESM projects stronger and more frequent extreme precipitation in the mountains and hot events in the deserts of the western U.S., with more wet periods in California as indicated by PDSI. In another VR-CESM refined-resolution region in China, VR-CESM projection indicates an increase in strength and magnitude of extreme precipitation in southern China and hot temperature extremes in eastern China. Geographic heterogeneity in PDSI projections is also evident as the North China Plain is projected to have more dry periods while the Three Gorges Basin is projected to not change much. This study demonstrates that the analysis of multiple extreme metrics is essential to provide an adequate understanding of how extremes may change in the future in a particular place.

Terrain Mapping for the Southwestern Desert of Iraq Using Interferometry Method from Sentinel-1A Images

Synthetic aperture radar Interferometry is a popular three-dimensional imaging technique for creating a Digital Elevation Model. Using traditional methods for creating DEMs and terrain mapping is one of the methods that require high cost and time-consuming, which has affected the creation and updating of terrain maps in Iraq, so this study aims to use the InSAR technology to generate DEM, which contributes to the creation of terrain maps. In this work, the synthetic aperture radar interferometry approach was used on the interference stack generated from a pair of Sentinel-1A images within the SNAP program to generate a DEM and a terrain map of the desert region in south-western Iraq. The elevations of the digital elevation model were compared with those of the RTK-GCPs points in the region of interest. The results obtained from this study are a terrain map with the contour lines generated from the digital elevation model created by the InSAR technique with an accuracy of 18 m, with the root mean square error of the DEM being 8.17. The outputs prove the effectiveness of InSAR technology in generating accurate DEM that contributes to creating terrain maps in less time and cost than traditional methods.

Gas Exchange and Chlorophyll Fluorescence’s Characteristics of Hyoscyamus muticus L. at Different Phenological Stages under Extreme Arid Environmental Conditions, South-Western Desert, Egypt

Gas Exchange and Chlorophyll Fluorescence’s Characteristics of Hyoscyamus muticus L. at Different Phenological Stages under Extreme Arid Environmental Conditions, South-Western Desert, Egypt

The youngest records of mosasaurid reptiles from the Upper Cretaceous of the South-Western Desert in Egypt

Mosasauroid squamates were abundant and had a worldwide distribution during the Late Cretaceous, but records from Sub-Saharan Africa are comparatively scanty and based mainly on fragmentary and isolated material. Here new mosasaur remains from the Maastrichtian (Upper Cretaceous) of Dakhla Oasis in the South-Western Desert of Egypt are recorded, including: a small, fragmentary right dentary of an indeterminate mosasaurine with a single tooth preserved in situ and an isolated tooth crown of the genus Globidens. This material stems from fossiliferous, calcareous sandstones with intercalated shales that form the lower portion of the Dakhla Formation, known to be an intertidal to subtidal deposit. Previously recorded mosasaur remains from the Eastern Desert in Egypt included Globidens phosphaticus, Platecarpus sp., and Igdamanosaurus aegyptiacus. In Africa, mosasaurs of the Maastrichtian age have been recorded from Morocco, Nigeria, Angola, the Democratic Republic of Congo, and Niger. The newly collected material from Dakhla Oasis currently constitutes the youngest record of mosasaurs in Egypt.

Determination of the Petro-physical and Natural Radioactivity Properties of Nubian Sandstone Aquifer at the Area of Northwest El Ain Village, Sharq El-Oweinat Area, Southwestern Desert, Egypt

The Nubian sandstone aquifer's hydrogeophysical and natural radioactivity parameters at the Northwestern part of El Ain village, Sharq El Oweinat, Southwestern desert, Egypt are resolved using geophysical well logging and natural radioactivity techniques. The study aims to monitor the phenomenon of appearing an unusual high gamma-ray at a zone of high resistivity record. A nest of well logs is collected to assess how the phenomenon is widespread. Results of correlated well logs are clarified that this phenomenon at zone between 80 and 100 m and zone of 200 and 230m depth is noticed. The petro-physical properties are estimated from the recorded well logs. The results showed that the percentage of the average of effective porosity % varies between 20 and 28.2%, while average vary from 2 to 12.5 %, which indicates that the aquifer of Nubian Sandstone is classified as a clean aquifer. The natural radioactivities of the studied area in the rock samples were evaluated using high-purity germanium (HPGe) detector. The results indicated that the average value of Th-232 is (51.32 ±4.92%) Bq/kg, Ra-226 is (29.03 ± 4.68%) Bq/kg while the radioactivity concentration of K-40 exists only in one sample with low concentration.

Detecting Crop Circles in Google Earth Images with Mask R-CNN and YOLOv3

Automatic detection and counting of crop circles in the desert can be of great use for large-scale farming as it enables easy and timely management of the farming land. However, so far, the literature remains short of relevant contributions in this regard. This letter frames the crop circles detection problem within a deep learning framework. In particular, accounting for their outstanding performance in object detection, we investigate the use of Mask R-CNN (Region Based Convolutional Neural Networks) as well as YOLOv3 (You Only Look Once) models for crop circle detection in the desert. In order to quantify the performance, we build a crop circles dataset from images extracted via Google Earth over a desert area in the East Oweinat in the South-Western Desert of Egypt. The dataset totals 2511 crop circle samples. With a small training set and a relatively large test set, plausible detection rates were obtained, scoring a precision of 1 and a recall of about 0.82 for Mask R-CNN and a precision of 0.88 and a recall of 0.94 regarding YOLOv3.

Leaching kinetics of uranium from Playa deposits at Atmur El-Kibeish area, South Western Desert, Egypt

ABSTRACT The leaching process of uranium (VI) from Atmur El-Kibeish rock sample located in the South Western Desert of Egypt in sulphuric acid solution by agitation leaching technique was investigated. The optimum leaching conditions achieved of acidic leaching are 150 g/L H2SO4, one-third solid/liquid ratio, 4 h agitation time, 125 µm size and at 60°C temperature. Under these conditions, the leaching efficiency of uranium was about 95%. The experimental data interpreted by a shrinking core model with diffusion control through a porous product layer. The leaching process follows the kinetic model: 1 − 3 1 − x 2 / 3 + 2 1 − x = kt with an apparent activation energy of 26.11 KJ/mole. Temperature, H2SO4 concentration and particle size are the main factors influence on the rate of leaching. Reaction order in H2SO4 was 1.22.

Water Use Efficiency of Acacia seyal (Del.) in extreme arid environment prevails in South-Western Desert, Egypt

The present investigation involves the studies of water use efficiency of Acacia seyal (Del.) seedlings under extreme arid conditions. Experiments were performed in a hyper arid environment to study the effects of drought stress using different water regimes at 12%, 9%, 6%, 4% and 2%. Calculated instantaneous water use efficiency was measured under full Photosynthetic Active Radiation range (0-2500μmols-1m-2). Acacia seyal showed maximum photosynthesis rate at 9% soil moisture content, and at high Photosynthetic Active Radiation levels. Maximum transpiration rate recorded at 9% soil moisture content at highest Photosynthetic Active Radiation. The maximum instantaneous water use efficiency was noticed at 4% soil moisture content at high Photosynthetic Active Radiation level. Acacia seyal maximized photosynthesis rate and minimized transpiration rate, giving maximum instantaneous water use efficiency at the high Photosynthetic Active Radiation and low soil moisture content levels.

Behavioral Response to High Temperatures in a Desert Grassland Bird: Use of Shrubs as Thermal Refugia

Birds inhabiting hot, arid ecosystems contend with trade-offs between heat dissipation and water conservation. As temperatures increase, passerines engage in various behaviors to reduce exposure to heat, solar radiation and insolation, and reradiation of heat from the ground. These responses to rising temperatures may result in subordination of reproductive urgency or nutrient acquisition to the need for thermoregulation. During studies on Arizona Grasshopper Sparrow (Ammodramus savannarum ammolegus) life history and ecology, we noted that these sparrows abandoned territoriality and foraging behaviors under certain circumstances in favor of cooler microsites. In this paper we document the extreme temperatures to which these and other ground-foraging and ground-nesting birds are exposed in southwestern desert grasslands, and we present evidence that A. s. ammolegus avoids exposure to extreme air and ground temperatures by using shrubs as thermal refugia. Our observations have implications for Arizona Grasshopper Sparrows and other desert grassland passerines in the southwestern United States, where the climate is projected to become hotter and drier. We provide some of the only behavioral data, and associated temperature data, associated with the use of thermal refugia by desert grassland birds. We encourage further studies that use more robust methods to supplement our observational data.

Bivalve borings in Maastrichtian fossil Nypa fruits: Dakhla Formation, Bir Abu Minqar, South Western Desert, Egypt

Disconnected aggregates of allochthonous fossil Nypa fruits occur in the Ammonite Hill Member of the Dakhla Formation (Maastrichtian), exposed at the Bir Abu Minqar section, south Western Desert of Egypt. In a pale brown, calcareous siltstone and/or fine-grained sandstone layer, the fossil fruits found are densely infested by the borings Teredolites clavatus and Apectoichnus longissimus. In the specimens described, wood borings assigned to A. longissimus are more abundant than T. clavatus. Remains of the boring bivalves are not preserved. These aggregates of bored fruits likely accumulated in a warm, shallow, well-oxygenated marine environment. Prior to final accumulation, Nypa fruits drifted in seawater only for a short time and exhibit evidence of biostratinomic alterations. The present study is the first to systematically describe the occurrence of both nominal ichnotaxa from the Maastrichtian rocks in Egypt.