Clay minerals damage quantification in sandstone rocks using core flooding and NMR

Sandstone oil reservoirs consist of different clay minerals such as kaolinite, illite, and chlorite. These clay minerals highly affect the formation damage during enhanced oil recovery (EOR) and well stimulation operations in these reservoirs. No attention was paid to investigate the effect of these clay minerals on the formation damage during different reservoir processes. In addition, no solution was introduced to mitigate the effect of clay minerals on the formation damage in sandstone reservoirs. In this study, the effect of clay mineral contents and type on the formation damage was studied in detail by injecting water and HCl as damaging fluids. Bandera grey, Berea, and Bandera brown sandstone rocks with various clay mineral contents were studied. XRD was used to characterize the sandstone rocks to determine the clay type and content in each rock. Two core plugs from each rock were selected for HCl and water injection. Core flooding experiments were performed to measure the initial and final permeability. In the core flooding experiments, fluids were injected into the cores at 25 °C and at a backpressure of 1000 psi. SEM was carried out before and after flooding for the tested rocks to locate the change in the clay distribution inside the rocks. The NMR analysis of core samples was done before and after flooding with the damaging fluid to quantify the formation damage and to find the possible damaging mechanism. NMR was used to locate the damage inside the rock due to the migration of clay minerals. Based on the core flooding, SEM, and NMR analysis, the maximum damage by the fresh water took place in Berea sandstone core due to fine migration and clay swelling. The illite clay mineral and chlorite can cause the formation damage on HCl injection. Illite can break down and migrates in the cores during the acid injection. In sandstone acidizing, chlorite clay mineral caused iron hydroxide precipitation inside the cores during treatment with mud acid. NMR showed that clay minerals plugged the pore throats of the rocks and reduced the rock permeability during the injection of fresh water

Adding the reliability on tree based topology construction algorithms for wireless sensor networks

Topology control is a technique used in wireless sensor networks to maximize energy efficiency and network lifetime. In previous literature, many tree based techniques have been proposed to save energy and increase the network lifetime. In tree based algorithms, the most promising solution is the formation of a network backbone, which serves on behalf of rest of the nodes in the network and therefore leading towards Connected Dominating Set (CDS) formulation. However, one imminent problem with all tree based solution is a compromise on network reliability. Therefore, to address reliability issues in tree based solutions, in this paper, we propose Poly3 which maintains cliques of size three in order to achieve network reliability on top of the CDS algorithm. This makes the network more robust to link removal. Our empirical and mathematical analysis reveals that Poly3 provides better reliability than algorithms of the same kind

Gross alpha and gross beta activity concentrations in the dust fractions of urban surface-deposited sediment in russian cities

Studies of gross alpha and gross beta activity in road-and surface-deposited sediments were conducted in three Russian cities in different geographical zones. To perform radiation measurements, new methods were applied which allow dealing with low mass and low volume dustsized (2–100 μm) samples obtained after the size fractionation procedure. The 2–10 μm fraction size had the highest gross beta activity concentration (GB)—1.32 Bq/g in Nizhny Novgorod and Rostov-On-Don, while the 50–100 μm fraction size was most prominent in Ekaterinburg. This can be attributed to the presence of radionuclides that are transferred through natural and anthropogenic processes. The highest gross alpha activity concentration (GA) in fraction sizes was found in Rostov-on-Don city within the 50–100 μm range—0.22 Bq/g. The fraction sizes 50–100 μm have a higher gross alpha activity concentration than 2–10 μm and 10–50 μm fraction sizes due to natural partitioning of the main minerals constituting the urban surface-deposited sediment (USDS). Observed dependencies reflect the geochemical processes which take place during the formation and transport of urban surface sediments. Developed experimental methods of radiation measurements formed the methodological base of urban geochemical studies. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.The study was supported by Russian Science Foundation (grant No. 18-77-10024). Institutional Review Board Statement: Not applicable. Informed Consent Statement: Not applicable

THE ROLE OF Er2O3 IN THE TeO2-ZnO GLASS SYSTEM: MECHANICAL AND GAMMA-RAY SHIELDING CHARACTERISTICS

Mechanical and shielding properties are affected by the addition erbium oxide in the Zinc-tellurite glasses

Natural Radioactivity and Radiological Hazard Effects from Granite Rocks in the Gabal Qash Amir Area, South Eastern Desert, Egypt

The existence of radioactivity linked to the heavy-bearing minerals in building materials—such as granite—has increased attention to the extraction procedure. Granite rocks play an essential economic role in various areas of Egypt. Thus, this study intended to detect the 238U, 232Th, and 40K activity concentrations in the examined granite samples and to determine the corresponding radiological risks associated with the granite. The studied rocks were collected in the Gabal Qash Amir area (south Eastern Desert, Egypt). The obtained results of the activity concentrations for 238U (193 ± 268) Bq/kg, 232Th (63 ± 29) Bq/kg, and 40K (1034 ± 382) Bq/kg indicated that there were moderate concentrations in the investigated samples, which were greater than the worldwide average. The radioactivity levels in the studied granite samples are due to the secondary alteration of radioactive-bearing minerals associated with cracks of granites (secondary minerals in muscovite granites are wolframite, uraninite, uranophane, beta-uranophane, autunite, xenotime, columbite, zircon, and monazite). The radiological risk assessment for the public from the radionuclides that were associated with the studied granite samples was predicted via estimating the radiological hazard factors, such as the radium equivalent content (362 Bq kg−1), compared with the recommended limit. The dosing rate Dair in the air (169.2 nGy/h), the annual effective dose both outdoors (AEDout ~ 0.21 ± 0.17 mSv) and indoors (AEDin ~ 0.83 ± 0.67 mSv), the annual gonadal dose equivalent (AGDE ~ 1.18 ± 0.92 mSv), as well as the external (Hex) and internal (Hin) hazard indices (>1), and another factor were associated with excess lifetime cancer risk. According to the statistical investigation, the studied granites were inappropriate for use in construction and infrastructure fields. They may induce health problems due to the radioactivity levels, which exceed the recommended limits. © 2022 by the authors.King Khalid University, KKU: KKU/RCAMS/22The authors would like to thank the Nuclear Materials Authority, Egypt. This work was supported by King Khalid University through a grant (KKU/RCAMS/22) under the Research Center for Advanced Materials Science (RCAMS) at King Khalid University, Saudi Arabia

DISTRIBUTION OF RADIOELEMENTS IN THE DIFFERENT ROCKS AROUND UM SALATIT MOUNTAIN AREA, EASTERN DESERT, EGYPT

Umm Salatit Mountain area is a part of the Central Eastern Desert of Egypt. It is com-posed of ophiolitic mélange, older granitoids, biotite granites, muscovite granites and post granitic dykes and veins

Assessment of Effective Doses Due to Inhalation of Natural Radioactivity in the Dust of Urban Environment

The inhalation exposure to dust in the urban environment for adult and child is very important due to health issues. The radionuclides Ra-226 and Th-232 were measured in the samples of urban surface deposited sediments. The average concentrations of Ra-226 and Th-232 in dust are 20.8 and 15.3 Bq kg-1, respectively. The effective dose is estimated depending on the daily activity and air dust concentration for the adult and child. The results show that the total effective dose received during 70 years by adult without outdoor activity is 0.74 μSv under exposure to air dust concentration 1×10-4 g/m3, which is typical for the city of Ekaterinburg. Critical scenario of exposure of an adult person to radioactive material in particulate matter in the air including such daily activities as training, bicycle driving and work in urban environment results in the total effective dose 17.8 μSv during 70 years at air dust concentration equal to the diurnal Maximum Permissible Limit (1.5×10-4 g/m3). Also, the critical children group can be exposed to radionuclides by inhalation through daily outdoor games, sport activity, training, bicycle etc (8 hours daily during vacation, 4 hours daily during school time, 2000 hours per year from 7 years to 17 years). The total effective dose for critical children group is 2.9 μSv. Thus, the effective doses due to inhalation of natural radioactivity in the dust in city of Ekaterinburg are relatively low in comparison ICRP reference level. © 2020 American Institute of Physics Inc.. All rights reserved

Effect of Various Proportions of Rice Husk Powder on Swelling Soil from New Cairo City, Egypt

Swelling soil leads to many types of constructional damages, deformations, and failures in the constructions’ roads, shoulders, and foundations. Depending on the amount of swell, they can be insignificant, moderate, or massive. This paper presents a method for swelling soil stabilization by adding rice husk powder (RHP) in variable percentages of 0, 5, 10, 15, 20, and 25 by weight of dry soil. The properties of swelling soil stabilization were investigated by various lab tests such as consistency limits (plastic limit, liquid limit, and plasticity index), swelling potential, swelling pressure, free swelling, and free swell index. The swelling soil was also mineralogically examined using X‐ray diffraction of clay mineralogy. This stabilization reduced the plasticity from 56% (extremely high plasticity) to 4.5% (low plasticity). Swelling potential (S) and swelling pressure (SP) decreased by 48% to 45.5, 44.7, and 34.6%, from 1003 kN/m2 to 800, 653, and 489 kN/m2 for the partial replacement of the soil by 5%, 10%, and 15% RHP, respectively. The results show that the present approach is very efficient for improving the swelling soil properties and that the optimal amount of added RHP of the swelling soil is 15%. It will also be a database aimed at reducing construction risks in the future. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.The APC was covered by “Dunarea de Jos” University of Galati, Romania. Acknowledgments: The author AE acknowledges the support of “Dunarea de Jos” University of Galati, Romania, for APC support

Hazards of Radioactive Mineralization Associated with Pegmatites Used as Decorative and Building Material

The present study aimed to assess the radiological hazards associated with applying the investigated granite in the building materials and the infrastructures applications. The investigated granites are classified into four categories: El-Urf, barren, colourful and opaque. El Urf monzogran-ite intrudes metagabbro diorite complex with sharp contacts. Based on the activity concentrations, the environmental parameters such as absorbed dose rate (Dair), annual effective dose (AED), ra-dium equivalent activity (Raeq), external (Hex) and internal (Hin) hazard indices were measured. The mineralized pegmatite is located in the southwestern foothill of the Gabal El Urf younger granite. It displays well-defined zonation of three zones: outer, middle and inner zones represented by potash feldspar, quartz and mica, respectively. The isorad map showed that El Urf monzogranite is barren (Up to 100 cps) surrounding an excavation of the studied pegmatite that exhibits moderate colorful mineralization (phase-I = 500–1500 cps) and anomalous opaque mineralization (phase-II = 1500– 3500 cps) pegmatites. The obtained results of radionuclides activity concentrations illustrated that the Opaque granites have the highest values of238U (561 ± 127 Bq kg−1),232Th (4289 ± 891 Bq kg−1) and40K (3002 ± 446 Bq kg−1) in the granites, which are higher than the recommended worldwide average. Many of the radiological hazard parameters were lesser than the international limits in the younger granites and barren pegmatites. All of these parameters were higher in the colorful and opaque mineralized pegmatites. The high activity and the elevated radiological hazard parameters in the mineralized pegmatites are revised to the presence of radioactive and radioelements bearing minerals, such as thorite, meta-autunite, kasolite, phurcalite, columbite, fergusonite, Xenotime and fluorapatite. Other instances of mineralization were also recorded as cassiterite, atacamite, galena, pyrite and iron oxide minerals. Thus, the granites with high radioactivity concentration cannot be applied in the different applications of building materials and ornamental stones. © 2022 by the authors. Li-censee MDPI, Basel, Switzerland.Funding: This research was funded by the Nuclear Materials Authority, Egypt. The APC was covered by “Dunarea de Jos” University of Galati, Romania, through grant no. RF3621/2021