Arabian Journal of Geosciences最新文献

One of the significant challenges in cementing operations is the ability to predict the rheological behavior of wellbore cement under bottom-hole conditions. Therefore, developing advanced fluid mechanics models is necessary to predict the rheological behavior of wellbore cement. This study focused on wellbore cement compositions in southern Iran’s exploratory oilfields, considering time, temperature, pressure, and cement stability during drilling and production operations. The proper exploratory and development oil wells’ cement formulation of the area shall be prepared according to the geological characteristics and static and circulation temperature at the beginning and end of the formation. It requires conducting various tests, such as compressive strength, free water, and thickening time, in the studied formations. Optimal compaction should be produced according to the amount of allowed slurry and comparing the data obtained from the tests. The values obtained from different formations were compared with those obtained from Bingham’s plastic and power fluids theories, and the very low deviation of the shear stress calculated at different radii of the rotary viscometer was compared. It was concluded that Bingham’s plastic model is the appropriate rheological model that describes the slurry’s rheological properties, such as plastic viscosity, shear stress, shear rate, and density. The novelty aspects of this work include a rheology modeling error range of 0.11 to 0.95% for wellbore cement compositions and the accurate representation of these cement’s rheological behavior. If this model is used to predict the rheological behavior of wellbore cement compositions before casing cementing, it can save drilling operations costs and time. It will also cause a correct evaluation of the reservoir layers and increase the production rate.

Impacts of structuration on the geomorphology and internal architecture of a Pleistocene feeder channel-ponded lobe system, Channel-1B (Ch-1B), on the continental slope of the Niger Delta, Nigeria, has been studied using a combination of 3D seismic stratigraphy and geomorphology methods. Mapping of diagnostic seismic facies, characterization of channel morphology and internal architecture, quantitative analysis, architectural element (AE) delineation, and reservoir modeling were carried out with the view to (1) establish Ch-1B geomorphology, internal architecture, and sediment fills, (2) investigate the influence of structuration on the evolution of internal architecture over time, and (3) assess the impact of the resulting internal architecture variability on reservoir modeling and development strategies. This study established a strong link between structuration and the evolution of feeder channel-ponded lobe systems. Evolution of Ch-1B has been summarized in five phases: (I) channel initiation dominated by sediment bypass and incision into fold-1, (II) major break in slope gradient resulting in deposition of ponded lobe-1, (III) complete fill of accommodation created in the ponded basin between folds 1 and 2, diversion of the channel axis westward by fold-2 and eventual incision into lobe-1 and fold-2 by the feeder channel as it adjusted to a new base level, (IV) deposition of lobe-2 in the footwall of fold-2, and (V) filling of the feeder channel, almost entirely, by turbidite muds thereby creating a channel plug that partitioned lobe-1 into two compartments. Understandings, from this work, of the impacts of structuration on geomorphology and internal architecture have been applied to AE delineation, reservoir modeling, and development strategies in terms of the number and type of wells needed to produce hydrocarbon in lobe-1 efficiently. Given that well costs represent a significant portion of field development costs, this study concludes that adequately delineating and modeling structurally influenced AEs will significantly affect field development economics.

The objective of this study is to carry out a hydrogeological mapping of the study area in order to precisely identify the favorable zones to the implantation of boreholes and water wells. This is with a view to optimizing success with the realization of catchment works and thus solves the problem of water shortage in the locality. The study area is covered by trachyte to the north and biotite granite which largely dominates the site and major NE-SW direction lineaments which correspond to the hydrographic network and are considered as fractures. Geological models from 1 and 2D inversions of electrical resistivity made it possible to visualize deep fractured rocks and consequently the different levels of aquifers. The study area is characterized by three domains, namely, a domain with high hydrogeological potential, characterized by hydraulic conductivity between 9.3817 and 2.7956 m/J, porosity between 35.5 and 28%, transmissivity between 232.34 and 27.36 m²/J, longitudinal conductivity between 0.298 and 0.046 Ω⁻¹, transverse resistance varying between 324.0566 and 2469.663 Ω/m², reflection coefficient between − 0.976 and − 0.321, and geoelectric anomalies essentially of types H, KH, and HKH; a second domain with average hydrogeological potential, characterized by hydraulic conductivity between 1.054 and 2.795 m/J, porosity between 25.74 and 30%, transmissivity between 27.36 and 16.42 m²/J, longitudinal conductivity varying between 0. 046 and 0.028 Ω⁻¹, transverse resistance lower than 37,460.7 Ω/m², reflection coefficient between − 0.321 and − 0.016, and geoelectric anomalies essentially of types H, KH, HKH, KHK, Q, and K; and a third range of low hydrogeological potential, characterized by hydraulic conductivity less than 1.45 m/J, porosity less than 24%, transmissivity of less than 16.43 m²/J, longitudinal conductivity less than 0.028 Ω⁻¹, reflection coefficient greater than − 0.16, and characterized by anomalies of types Q, HK, and K. The area with high hydrogeological potential is where the lineaments most closely correspond to fractures. Its characteristics make it a favorable domain for any hydraulic engineering project.

Morphogenetic properties and geochemical compositions were analyzed and assessed to improve our understanding of pedogenesis and geochemistry of wetland soils on the Abeokuta formation of Ogun State, Nigeria. Three profiles were dug to a depth of 1.2 m except where the water table is high, and examined for their morphological, physical, chemical, and geochemical compositions using standard laboratory techniques. Gleying (mottles) were present in some of the subsurface horizons, and dark greyish colour dominates the soil matrix. The particle size is dominated by sand fractions and the clay fraction increases with depth. The soil pH was moderately acid to neutral (4.6–6.8) and the organic carbon contents were low to high (4.9–43.1 g/kg). The exchange site was dominated by Ca and Mg, while Fe and Mn contents were higher among the micronutrients. Kaolinite, quartz, and degraded mica were the dominant minerals in the clay fractions. The geochemical results reveal that the order of abundance of major oxides is SiO₂ > Al₂O₃ > Fe₂O₃ > CaO > MgO > Na₂O > TiO₂ ≥ K₂O. Geochemical indices point to a moderate degree of weathering and pedogenesis. Higher contents of SiO₂ and Al₂O₃ and calcium in the surface layers indicate relative enrichment of minerals during weathering and nutrient cycling by vegetation.

The utilization of oil shale ash in developing environmentally sustainable filling materials for subterranean mines presents a promising ecological approach, albeit with typically low ash content. In this study, the filling material was prepared by adding oil shale ash and slag. The study examines the physical and mechanical properties of filling materials predominantly composed of oil shale ash slag, sourced from the Baoming open-pit mine in Jimusar, Xinjiang. Comprehensive testing and analysis are conducted to examine the chemical composition, mineral composition, and particle grading of oil shale ash, cement, and fly ash. The research prepared 45 cubic specimens measuring 50 mm × 50 mm × 50 mm and analyzed their mechanical responses under uniaxial compression conditions, employing varying dosages of ash, cementitious materials, and water as critical variables. The results indicate that the primary constituents of oil shale ash are silica (SiO₂) and aluminum trioxide (Al₂O₃). When the oil shale ash content ranges from 60 to 70%, with a cement-fly ash ratio of 7:1 and a water content of 11%, the filling material attains its highest average compressive strength of 16.37 MPa at 28 days. Furthermore, increased cement content in the cementitious material correlates with higher compressive strength in the filling material. This research underscores the potential of oil shale ash–based green mining filling materials to restore goaf.

The efficacy of remote sensing techniques for mineral exploration has been proven through several geological investigations. Therefore, this study used remote sensing techniques to delineate uranium prospective zones in the oriental part of Reguibat shield. This region is desert, flat and uncovered by vegetation and presents suitable characteristics for use of satellite images. Radiometric calibration, atmospheric correction, colour composite, principal component analysis (PCA), lineament extraction and band ratios were the main methods performed for the pre-processing and the processing of Landsat 8 OLI images. The findings of the current study revealed lithological units dominated by felsic rocks in association with metasediment, highlighted using band composite (bands 7, 5 and 3, then 7, 2, and 1, in RGB), PCs (PC1, PC2, and PC3) and band ratio (7/5, 5/4, and 6/7 in RGB). The lineament extraction and analysis indicated major deformation trending NNE-SSW affecting geological units of the area. The prospective uraniferous zone delineated showed a spatial distribution in relation with an identified shear zone which suggests a reasonable structural control of the mineralization. The results from this study were validated with existing data from previous map and ground truthing from fieldwork, and they showed high level of agreement. The result of this study further demonstrated the applicability of Landsat 8 OLI as suitable lithological mapping tool in the desert areas. The methodology employed in this research has wide-ranging applications in the identification and delineation of potential uranium-rich regions using remote sensing techniques. For uranium exploration purpose, this approach can be effectively utilized in various other regions to delineate new uraniferous area within the Reguibat shield, as well as in arid and semi-arid areas across the globe.