Arabian Journal of Geosciences最新文献

An important concern when using site-available marginal soils as backfill is their tendency to accumulate moisture due to low hydraulic conductivity, which leads to reduced strength and cause serviceability issues. This problem can be mitigated by reinforcing the above soils with geocomposites, which serve a dual function of structural reinforcement and drainage improvement. In this study, large direct shear box tests were conducted to determine the interface shear strength between geocomposites and marginal soils under varying density, normal stress, deformation rate, and moisture content. Each variable affected the amount of water migrating toward the geocomposite strips during shearing. The migrated water was maximum in soils compacted at optimum moisture content (OMC). Water migration was the least in samples compacted on the dry of OMC. The moisture also affected the interface friction efficiency, as it was found to increase with the increase in the sample’s initial moisture content. The friction efficiency reached a transient peak when the sample was compacted at OMC. It was also affected by the deformation rate. Interface friction ratio increased with the increase in dry density and the use of large size particles in the samples.

The petroliferous studied block (Zhen 11 block, Zhenwu oilfield, Gaoyou sag) is situated in the North Jiangsu basin, China. The studied Sanduo formation is the target zone with two members. The main objective of the studied formation is to evaluate the reservoir characteristics of the Sanduo formation. To accomplish the aims, the core data, logging data, mercury injection capillary pressure (MICP), Cathodoluminescence (CL), X-ray diffraction (XRD), and Petrographic thin sections analysis of more than 10 wells have been analyzed. The reservoir rock types are felspathic litharenite and lithic arkoses. The grain rounding and sorting are deprived, with low texture maturity with moderate to good reservoir characteristics (10% to 30% porosity and 0.4 × 10^− 3µm² to 8000 × 10^− 3µm² permeability). Mechanical compaction, quartz and calcite cement, feldspar dissolution, and alteration of clay minerals are the main diagenetic processes. Thick-bedded coarse-grained sandstones have been deposited in a channel, where primary pores are common and the rock has strong compaction resistance, resulting in better reservoir quality. In the channel bay and estuary sedimentary environment, fine-grained and thin-layer sandstones are deposited, which represent weak anti-compressive capacity and rapid attenuation of pores during burial, indicating low reservoir characteristics. Carbonate cements block pores that significantly reduce the reservoir properties. Type I and type II zones are favorable reservoirs that are primarily developed in the superimposed development positions of meandering channel, side beach, braided channel, and underwater distributary channel at the front of the delta. The sandstone deposited in these environments has a high content of quartz and feldspar with good sorting. The rock has strong anti-compaction ability during burial and compaction, and the original intergranular pores are well preserved, which permits the acidic fluids migration into the reservoir. Due to that, dissolution can create secondary pores that enhance the reservoir characteristics.

Geochemical analysis of sediment samples from the Lekki Lagoon was carried out to provide evidence for provenance, chemical weathering conditions and tectonic settings. Following sample digestion, Inductively Coupled Plasma Emission Spectroscopy (ICP-ES) and Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) were subsequently employed for the quantification of major and trace elements respectively. Higher Al/Si ratios in Lekki Lagoon Sediments (LLS) were observed in mud-rich sediments, whereas the non-cohesive fine- to medium-grained sands are enriched in silica due to lower Al/Si ratios. Geochemical characterization indicates that the sediments are predominantly comparable to quartz arenite and litharenite, with a few samples resembling subarkose and sublitharenite. They display a broad spectrum of compositional maturity, ranging from low to very high. The plagioclase index of alteration (PIA) and chemical index of alteration (CIA) indicate that most LLS samples originated from moderately to strongly weathered silicate sources. However, the inclusion of the Fe and Mg (FM) constituents in the ternary plot expressed as A-CNK-FM indicated weak to strong chemical weathering. The geochemical discrimination diagrams collectively suggested that the Lekki Lagoon sediments (LLS) were predominantly derived from felsic to andesitic source rocks, with compositional signatures pointing to a passive margin setting. Minor but notable contributions from continental island arc sources indicated a mixed provenance influenced by multiple tectonic regimes.

Boron contamination in water sources represents a critical environmental and public health concern due to its toxicity and adverse impacts on ecosystems and human well-being. This study systematically investigates calcium oxide (CaO) as an effective adsorbent for boron removal from aqueous solutions. CaO is considered a promising candidate for water treatment owing to its high reactivity, large surface area, and facile production. Key operational parameters, including pH, adsorbent dosage, initial boron concentration, contact time, and temperature, were thoroughly examined to optimize the adsorption process. The highest removal efficiency was achieved at pH 9, with an adsorbent dosage of 0.4 g/50 ml and an initial boron concentration of 16.5 mg/L. To further enhance removal performance and evaluate factor interactions, a 2³ factorial experimental design was implemented using Minitab 18.0, enabling both optimization and statistical assessment of the parameters. The adsorption mechanism was analyzed through isotherm, kinetic, and thermodynamic models. Equilibrium data were best described by the Sips isotherm model, indicating the presence of heterogeneous adsorption sites, while the adsorption kinetics followed the pseudo-second-order model, suggesting that the adsorption rate is primarily controlled by interactions between boron ions and the CaO surface. Thermodynamic analysis revealed that the process is endothermic and non-spontaneous under the tested conditions Furthermore, the influence of temperature on adsorption efficiency was systematically assessed, showing an increase in boron uptake with rising temperatures, which is attributed to enhanced diffusion rates and increased surface reactivity. The study also highlights the scalability of CaO-based adsorption systems and their potential integration into conventional water treatment processes. These findings provide comprehensive insights into designing sustainable and cost-effective strategies for mitigating boron contamination in real-world water purification applications.

Pore pressure prediction is an essential input in drilling programs. An integrated rather than a single approach for pore pressure prediction delivers an accurate or near accurate results required for drilling without characteristic geohazards and enhanced cost implication. A one-dimensional prediction from petrophysical data served as an input VES-V_p regression. Prestack Depth Migration seismic was the source of Effective velocity picked from seismic semblance. The use of Dix equation was employed not only to convert effective velocity to interval velocity but to also provide the platform for the converting stacking velocity to Normal Moveout Velocity. The interval velocity served as an input data to generate the pore pressure volume of the field’s seismic gather after a checkshot from a well within the field was used to calibrate the seismic data. Results show that the integration of both log data and seismic velocity delivered a deeper pore pressure prediction of the subsurface and that of the entire seismic volume. While the use of log could deliver pore pressure at a depth of 12,521.62ft, the seismically-derived pressure could train as deep as 15,914.4ft. Pore pressure could have been predicted for deeper seismic data, the use of short cable length in acquisition and the non-availability of good data beyond 3000 ms. constrained seismic data acquisition. The field investigated is mildly overpressured.

Rainfall and in-situ leaching, a mining process involving the injection of chemical solutions to extract rare earth elements, are the two primary triggers for landslides in ion-absorbed rare earth deposits. While previous research has often treated these factors in isolation, this study specifically investigates their coupled effect. We developed a numerical model to simulate slope seepage and stability, employing the finite element method for unsaturated seepage analysis and the limit equilibrium method for stability calculation. The model was used to determine rainfall intensity-duration (ID) thresholds for slope failure under varying durations of leaching cessation prior to rainfall. The results demonstrate that a longer interval between stopping injection and the onset of rainfall significantly enhances slope stability. Furthermore, we identified that high pore water pressure is a critical failure mechanism. Consequently, a novel landslide early warning model was established based on quantitative pore water pressure thresholds, which can be categorized into different warning levels. This model provides a practical and scientific framework for mitigating landslide risks in rare earth mining areas, enabling a better balance between safety and production efficiency.

Urbanisation and industrialisation have led to heavy metal contamination of road dust, posing a global health threat. Gaya (Bihar) has witnessed an upsurge in the population and undergone rapid urban development in the past decade, leading to widespread dust prevalence. The present study evaluates the heavy metal abundance and ecological risks associated with roadside dust at eight prominent bus stands in Gaya, Bihar (India). The collected roadside dust samples were assessed for five toxic heavy metals including copper (Cu), lead (Pb), cadmium (Cd), zinc (Zn), and nickel (Ni). The minimum and maximum concentration ranged from 26.03–54.23 mg kg^–1, 1.68–34.11 mg kg^–1, 114.44–322.81 mg kg^–1, and 3.50–13.27 mg kg^–1 for Cu, Pb, Zn and Ni respectively. Cd was undetectable in the current study. Average concentrations of Cu and Zn were higher than the upper continental crust (UCC) values, while Pb concentrations exceeded UCC values at all sites except Panchanpur bus stand. Various indices (concentration factor, contamination degree, pollution load index, and index of geoaccumulation), employed to evaluate the risks associated with dust pollution, indicated low to moderate heavy metals contamination. However, the potential ecological risk factor and potential ecological risk index revealed a low to no risk associated with heavy metals. This study, the first of its kind near a UNESCO World Heritage site, establishes a crucial baseline, necessitating further evaluation of future risks to human health and the environment.

Geothermal energy is increasingly recognized as a vital renewable energy source with significant economic and environmental benefits, contributing to the global transition to cleaner energy. This paper examines the economic feasibility and environmental impact of geothermal energy development, focusing on the high initial costs of drilling and infrastructure, which are offset by low operational costs and long-term sustainability. Although geothermal projects require substantial upfront investment, particularly in drilling, they offer a reliable, low-maintenance energy solution with operational lifespans of 20 to 50 years. The paper analyzes cost–benefit dynamics, comparing the levelized cost of electricity (LCOE) of geothermal power with other renewables such as wind and solar, showing that geothermal is competitive in regions with high resource potential. In addition to cost considerations, it discusses geothermal energy’s environmental advantages, emphasizing its low greenhouse gas emissions and carbon intensity, which make it one of the most sustainable energy sources. Reducing emissions is crucial for addressing climate change and meeting global carbon-reduction targets. The paper also highlights the importance of resource management to avoid overexploitation and depletion. Strategies such as fluid reinjection and the development of enhanced geothermal systems (EGS) are presented as ways to ensure long-term viability. Furthermore, it presents successful case studies from California, Alberta, the Philippines, and the United Kingdom, where abandoned oil, gas, and exploration wells have been repurposed for geothermal energy production. These case studies demonstrate the cost-saving and environmental benefits of using existing infrastructure, reducing the need for new drilling and minimizing environmental impacts. By leveraging advanced technologies and innovative approaches, geothermal energy can provide a sustainable, low-carbon energy source that addresses both economic and environmental challenges. The paper concludes by underscoring geothermal energy’s potential to contribute significantly to global energy sustainability, offering a reliable, eco-friendly solution for the future.

Monitoring waterflooding operations is vital for sustaining good production performance in oil reservoirs with complex geometries or limited well control. Traditional methods such as finite difference, material balance, and plotting techniques like Hall plot and bubble plot are time-intensive and sensitive to grid resolution. In this study, the streamline simulation approach using MBAL software was employed to assess the effects of boundary conditions (no-flow and constant pressure) and injection well pattern designs (five-spot, seven-spot, and nine-spot) on oil recovery efficiency. By comparing various boundary conditions and patterns, the study aims to demonstrate the efficiency and accuracy of streamline simulation-based models for waterflooding monitoring and surveillance. A hypothetical waterflooding model incorporating different boundary conditions and pattern types was developed and analyzed for improved oil recovery optimization strategies. The study revealed sweep efficiencies of 8.89% (no-flow), 68.28% (constant pressure), 96.46% (five-spot), 91.24% (seven-spot), and 99.64% (nine-spot), with corresponding recovery factors of 5.75%, 44.18%, 75.02%, 70.91%, and 77.50%, respectively. These results demonstrate how boundary conditions and pattern layout dramatically impact displacement performance. The nine-spot pattern under constant pressure exhibited the highest sweep and recovery, with streamline simulation offering a rapid and computationally affordable method for such comparative evaluation. Findings highlight the importance of early-stage pattern screening in IOR planning.