ABSTRACT Accurate estimation of relative permeability is essential for dynamic reservoir simulation and development planning. This study presents an integrated approach that utilises Nuclear Magnetic Resonance (NMR) log data to derive relative permeability curves for different rock types in a gas-bearing reservoir. NMR-derived porosity has been corrected for gas effects, and then absolute permeability is computed using Coates method. Flow Zone Indicator (FZI) analysis is performed to classify hydraulic flow units, which aids in identifying distinct rock types. A pseudo-capillary pressure curve is reconstructed from substituted T2 distributions using a method based on the relationship between irreducible water saturation and geometric mean T2. These pseudo-capillary pressure curves are then used to estimate normalised saturation and to compute relative permeability curves using the Corey method. This workflow demonstrates that NMR data, when appropriately processed, can serve as a powerful tool for estimating relative permeability in the absence of extensive laboratory measurements, offering significant value for reservoir characterisation and simulation workflows.
ABSTRACT We report here for the first time the spectroscopic investigations on St. Severin meteorite using Fourier transform infrared spectroscopy, focusing on its mineralogical phases. The St. Severin LL6 chondrite is dominated by Mg-rich olivine, with whole-rock composition of SiO2 (40.50-40.75 wt%), MgO (25.40-25.58 wt%), and FeO (18.60-18.80 wt%). Minor oxides include Al2O3, CaO, Cr2O3, TiO2 and MnO. Infrared spectroscopy shows characteristic olivine bands near 980, 885, 835, 600, and 500 cm−1, with positions reflecting the Mg/Fe ratio. Diffuse reflectance spectra in the 10 and 20 μm regions are analogous to Fo-rich dunite and consistent with interplanetary dust and astrophysical silicate observations, confirming Mg-rich olivine dominance. Minor variations in band widths and intensities likely arise from Fe content, grain size, and crystallinity. These results demonstrate the mineralogical similarity between St. Severin, terrestrial dunites, and cosmic silicates, highlighting the extensive occurrence of Mg-rich olivine in meteoritic and astrophysical environments.
ABSTRACT This synthesis integrates five decades of regional and local structural mapping, geochemistry, geochronology, and geophysical data to propose a unified tectono-metallogenic model for Neoarchaean orogenic gold mineralisation in the Dharwar Craton (DC). The paper advocates a working hypothesis that the Craton evolved within a Phanerozoic-style convergent plate tectonic regime, characterised by westward low-angle subduction of oceanic lithosphere beneath an extant Mesoarchaean continental fragment. This process drove the inversion of Neoarchaean ensialic half-graben volcano-sedimentary basins into west-verging fold-thrust belts, emplacement of tabular plutons of granitoids, followed by craton-scale sinistral shearing. These structural events provided the necessary architecture for vertical, channelised fluid flow, resulting in a craton-wide gold depositional event within a short pulse between 2.54-2.52 Ga. The proposed framework unifies diverse geological datasets and offers critical insights for future gold exploration strategies within the Craton.
ABSTRACT Particle invasion is a major contributor to well impairment in waterflooding operations, resulting in permeability (K) reduction and formation plugging. It significantly affects the injectivity decline. In this study, supervised Machine Learning (ML) utilising an Artificial Neural Network (ANN) has been employed to model and predict K decline due to particle invasion in core flooding experiments. Mathematical modelling has traditionally been used for K decline, but a single model struggles to generalise across different experiments. This is where Artificial Intelligence (AI) and ML play a crucial role by training a model on a large dataset, incorporating data from numerous experiments. This paper has successfully demonstrated the feasibility of the proposed approach using data from five distinct core flooding experiments obtained from published works for model training. The model exhibited excellent performance in predicting K, with an R2 value approaching 1. Additionally, the logistic regression model accurately predicted the type of filter cake formed, achieving a classification accuracy score of 1. These findings have significant implications for designing waterflooding and injection operations, which are becoming increasingly important in meeting the growing oil demand.
ABSTRACT Landslides are natural hazards that result in fatalities, damage to infrastructure, and harm to the environment. In recent years, the advancement of remote sensing technology, particularly the UAV (Unmanned Aerial Vehicle) in the domain of landslide studies, enables easy data acquisition, mapping, and monitoring with improved spatial coverage and temporal frequency. Additionally, it optimises fieldwork by accessing inaccessible areas safely. This paper provides an in-depth review of the application of UAVs in landslide studies. Different types of drones, hardware and software components and the steps and stages for operating UAVs are presented. This paper gives an overview of the published literature and documented cases that describe the advancements and applications of UAVs in landslide studies. This paper also includes a case study depicting the application of UAVs in the Indian Himalaya. Furthermore, this review delves into the challenges and prospects of UAVs in landslide mapping and monitoring, leading to enhanced early warning systems and better decision-making processes to mitigate the impact of landslides.
ABSTRACT The Kotanka gabbroic anorthosite, within the Wajrakarur Kimberlite Field, Eastern Dharwar Craton of southern India, represents a newly recognised plagioclase-rich cumulate body. The gabbroic anorthosite is dominated by cumulate plagioclases (~75-85%) with intercumulus augite and Fe-Ti oxides and displays a meso-cumulate texture typical of massif-type anorthosites. Mineral chemistry reveals a bimodal plagioclase composition: early calcic phenocrysts (An75-95) and later sodic groundmass feldspars (An40-50), indicative of fractional crystallisation within a deep crustal magma chamber. Clinopyroxenes are Mg-rich augites (Mg# 0.55-0.82), consistent with the evolution from a tholeiitic basaltic melt. Bulk-rock geochemistry affirms the cumulate origin with high Al2O3 (23-25 wt%) and CaO (9-10 wt%), and modest FeOt-MgO (~5-6 wt%). However, an unusually elevated K2O content (~3.3-3.9 wt%) and enriched Rb and Ba suggest post-magmatic K-metasomatism. XRD analysis corroborates widespread alteration of plagioclase to illite, muscovite, and chlorite, indicating K-rich fluid interaction under low-grade metamorphic conditions. This overprint modified the original mineralogy and geochemistry, altering the feldspar and enriching the rock in potassium. Collectively, the data support crystallisation from a mantle-derived basaltic magma via fractional accumulation of plagioclase, subsequently altered by the hydrothermal fluids. Kotanka gabbroic anorthosite thus exemplifies a massif-type gabbroic anorthosite formed by magmatic differentiation and later overprinted by metasomatism and provides valuable insights into the petrogenetic and postemplacement processes involved in anorthosite genesis.
