Arabian Journal of Geosciences最新文献

Field and petrographic studies of the Qishn Formation provide insights in to sequence stratigraphic and reservoir attributes of the formation. The reservoir properties are controlled by complex interaction between depositional textures and diagenetic products. The Barremian-Aptian Qishn Formation was deposited between Precambrian basement rocks and marl-dominated Albian Kharfort Formation. The Qishn Formation consists of lower sandstone (Shabon Member), middle unit dominated by lime mudstone (Hinna Member), and upper bioclastic limestone with dolostone interbeds (Hasheer Member). The formation defines a transgressive-regressive sequence with maximum flooding surface (MFS) at the top of the Hinna Member. The petrographic and diagenetic analyses indicate that Shabon and Hasheer members constitute good reservoirs. The Shabon Member is dominated by friable medium- to coarse-grained arkose to lithic arenite with porosity as high as 20%. Despite a burial depth of ~ 5 km, the sandstone maintains most of its intergranular pores. The diagenetic features include early calcite cement followed by burial compaction. However, since most of the pores were already filled by calcite cement, volumetric reduction due to compaction was minimal. Post-compaction dissolution of the early calcite cement resulted in restoration of the intergranular pores. The Hasheer Member consists of extensively cemented bioclastic packstone to rudstone with porosity < 6% and sucrosic dolomite with intercrystalline and vuggy pores reaching up to 15%. The mud-dominated Hinna Member can be considered as potential cap rock for any fluids within the Shabon Member, whereas the marls of the Kharfot Formation constitute potential caprock for the preservation of fluids in the Hasheer Member.

The ongoing refinement of bearing capacity equations remains pivotal in soil mechanics and foundation engineering, reflecting its critical role in ensuring design efficacy and construction safety. This study conducts a thorough evaluation of classical bearing capacity methods—Terzaghi, Meyerhof, Vesic, and Hansen—and methods included in various design standards, such as EN1997:2004, prEN1997:2023, GEO, AASHTO, FHWA, and API. It explores the performance and applicability of these approaches, identifying areas for potential improvement. In response to identified challenges, the paper proposes the integration of a unified depth factor. This new factor is designed to be applicable across all N-terms, providing a more versatile and accurate tool for bearing capacity predictions. Unlike the original depth factors unique to each method, which may not fully address complex soil and footing conditions, the unified depth factor is developed to enhance prediction accuracy for a wide range of conditions, including both flexible and rigid footings under varying flow rules (ψ = 0 and ψ = φ). This depth factor corrects for modeling errors, emphasizing the importance of pairing the correct set of N-factors with their corresponding depth factor. By offering a singular depth factor that aligns with the outcomes of finite element analysis, this paper not only simplifies the computational process but also enhances the accuracy of bearing capacity predictions across a diverse range of soil conditions and footing types. The comparative analysis, based on finite element analysis, validates the proposed method’s effectiveness, showcasing its potential to significantly refine foundation design practices by comparing it with both traditional and newly developed depth factors.

Rainfall-runoff simulation models require calibration to ensure accurate results. The present study assesses the efficacy of the Melody Search algorithm (MeS) in auto-calibration of the SWAT, by comparing it to other commonly used calibration methods in SWAT-CUP, namely, SUF12, GLUE, ParaSol, and PSO. In order to assess the MeS algorithm’s performance, the continuous rainfall-runoff simulation was implemented using daily time-step data from the Taleghan Basin in northern Iran, spanning a 10-year period. The calibration of parameters was established through developing a FORTRAN program. The Nash–Sutcliffe efficiency (NSE) index indicator in SUFI2, GLUE, ParaSol, PSO, and MeS algorithms was found to be 0.647, 0.6, 0.628, 0.625, and 0.66, respectively. Thus, based on these results, the proposed MeS algorithm outperforms all the native calibrating methods in SWAT in all iterations. MeS specifically outperforms all native approaches in reaching a solution after 100 iterations. The results imply that MeS is an algorithm that quickly converges and functions as a reliable calibration technique for SWAT applications.

This paper proposes a new method for interpreting the results of field studies within three steady-state regimes to estimate the dynamic well drainage area (i.e., pressure disturbance area) for a gas condensate well. The technique takes into account the compaction properties of a reservoir and the thermodynamic properties of a gas condensate fluid system. The described method has been developed based on the Binary filtration model of a multicomponent hydrocarbon fluid system, which considers the gas condensate mixture as a composition of two pseudo-components. This model takes into account the phase transformation of pseudo-components and the mass exchange between the phases. The implementation of the new method requires data on well flow rates measured within three different steady-state conditions. The presented algorithm is verified using several examples covering wide range of formation pressure changes and rock compaction factors. Applying this methodology, for example, with PVT data of gas condensate mixture of the VII^th horizon of the Bulla-Deniz field (Azerbaijan) at various reservoir and bottomhole pressures, it was revealed that the mismatch between calculated values of the well drainage area and the actual values varied within a range of 0.97 to 2.6% and 0.58 to 1.9% error for non-deformable and deformable formations, respectively. With the introduction of the concept of an “imaginary well” (enlarged well), an expression was obtained for monitoring the activity of an aquifer. And for the first time, an approach for the numerical assessment of aquifer activity based on Jamalbeyli indexes has been proposed.

The advance rate (AR) of tunnel boring machines (TBMs) plays a pivotal role in evaluating their efficiency in tunnel engineering projects. This study focuses on the development of precise prediction models for TBM performance employing advanced algorithms, including gene expression programming, time series analysis, multivariate regression, artificial neural networks, particle aggregation algorithms, genetic algorithms, adaptive neural fuzzy inference systems, and support vector machines. The AR, serving as a performance metric, becomes the specific target for prediction models. A test database comprising 3597 datasets was curated from a tunneling project at the Sar Pol Zahab, Bazi Daraz water transfer tunnel. Utilizing 21 parameters as input variables, intelligent AR models were formulated based on comprehensive training and testing patterns, incorporating geological features and the key machine parameters influencing AR. Quantitative evaluation of the models involved statistical indicators such as root mean square error (RMSE), coefficient of determination (R²), and variance calculation. Comparative analysis based on RMSE, MAE, MAPE, VAF, and R² superior gene expression function models showed that the gene expression algorithm with 1.41, 0.66, 6.33, 98.88, and 0.95 ahead of the nose is better than other approaches. These results underscore the efficacy of the gene expression programming-based model, suggesting its potential to yield a novel functional equation for accurate TBM performance prediction.

Lateritic gravels are extensively used in road construction and other civil engineering structures. Depending on various parameters, genetic characteristics vary from one locality to another. Geological analyses were conducted to investigate their influence on the geotechnical properties of lateritic gravels developed on gneiss for their better use in road construction. Petrographical, mineralogical, and geochemical results show the existence of two types of lateritic gravels in the study area: yellowish to brownish lateritic gravels of humid savannah (LGHS) and reddish lateritic gravels of dry savannah (LGDS). These materials mostly content quartz, kaolinite, hematite, goethite, muscovite, gibbsite, anatase, Fe₂O₃, Al₂O₃, and SiO₂. The hematite, goethite, Fe₂O₃, and Al₂O₃ content has a positive influence on the geotechnical behavior of the studied lateritic gravels, while the content of quartz, muscovite, and SiO₂ has the opposite effect. The evaluation of alterologic parameters show that the degree of lateritization has a positive influence on CBR, maximum dry density, and the specific gravity. Three CBR models with determination coefficients R² = 0.85, 0.87, and 0.88 were established by associating the genetic characteristics of the materials with geotechnical parameters. The outcomes of the present study show that geotechnical properties of lateritic gravels are significatively influenced by their genetic characteristics. Is therefore important to performed geological studies for a better use of lateritic gravels in road construction.

This research investigates the seismic response of sand-made wrap-faced retaining walls using a shaking table, focusing on the impact of varying relative densities and frequencies on the dynamic characteristics of the walls. Two types of sand have been used to prepare retaining wall model for shake table testing. They are “Local” sand and “Sylhet” sand. A 2 m × 2 m computer-controlled servo-hydraulic single degree of freedom shaking table facility in geotechnical laboratory of Bangladesh University of Engineering and Technology (BUET) has been used to test the model under sinusoidal loading. Here, different kinds of combination of seismic waves of different frequencies are selected to apply on different densities wrap-faced wall model in order to observe their dynamic characteristics. The relative densities of Sylhet sand are chosen 48%, 64%, and 80% for preparing the model wall. On the other hand, 48%, 64%, and 80% are selected for preparing Local sand model. Portable traveling pluviator (PTP) developed by (Hossain and Ansary, Innov Infrastruct Solut 3:53, 2018) has been used here to construct the uniform wrap-faced retaining wall model. Tests are performed under three different surcharge pressures like 0.7 kPa, 1.12 kPa, and 1.72 kPa. Sinusoidal tests are implemented for three base accelerations (0.1 g, 0.15 g, and 0.2 g) and for eight different frequencies (1 Hz, 2 Hz, 3 Hz, 5 Hz, 8 Hz, 10 Hz, 12 Hz, and 15 Hz). In the end, from these test results, it has been observed that acceleration amplification is inversely proportional to relative density. Further, acceleration amplifications are increased with the rise of frequencies. On the other hand, face displacement has been decreased with the increase of the relative density and frequency at same normalized elevation. The test results have been compared with (Krishna and Latha, Geosynth Int 14:355–364, 2007), although they used poorly graded sand and different scaling factor of the retaining wall model. It has been also noticed that the Sylhet sand retaining wall shows more acceleration amplification during sinusoidal loading than the Local sand retaining wall. In this research, the impact of different kinds of relative densities and frequencies on wrap-faced retaining wall model under sinusoidal testing has been observed.

The Blue Nile Basin is one of the frontier basins in Ethiopia, where there is very limited sub-surface data to understand the petroleum system of the basin. In frontier basins, only comparative analogs can be used for reservoir studies. The main purpose of the study is to elucidate the importance of facies, stratigraphic, and provenance study to comprehend the nature of the reservoir rock in the Blue Nile Basin. The study reveals the presence of eight lithofacies in the study area. The textural, structural, and compositional data and the general fining-upward sequence of the upper sandstone attest fluvial deposition by braided river system. The presence of the dominant medium-grained quartz arenite with moderate cementation (diagenesis) effect in the upper sandstone is an indication for the existence of good reservoir rock in the basin. The upper sandstone is relatively thinner in the study area, average 75 m, compared to the central part of the basin, average 220 m, and this depicts the geometry of the upper sandstone which pinches out to the north of the basin. Comparison of provenance and cement types of the upper sandstone in the study area and central part of the basin revealed the existence of similar nature of reservoir rock in the basin.

Due to the fact that traditional rock constitutive models are constructed under static loading conditions and cannot accurately describe the mechanical behavior of rocks under dynamic loading, it is of great theoretical value to study the dynamic constitutive theory exhibited by layered shale under impact loading. This article constructs a dynamic damage constitutive theory for layered shale based on the dynamic mechanical deformation and failure characteristics exhibited by shale with different bedding dip angles in impact loading experiments. Based on this theoretical model, a program of the finite element method was developed to numerically simulate the impact test process of layered shale. The results indicate that the finite element program developed based on the dynamic damage constitutive model in this article can effectively reflect the dynamic mechanical characteristics of layered shale during impact loading.