Advances in Geological and Geotechnical Engineering Research

Hydrogeological Investigations of Paghman Valleys in Kabul, Afghanistan

Hafizullah Rasouli — 2024-02-18

Paghman valleys are located at the foothills of the Hindu Kush Mountain range (Afghanistan) and consist of dissimilar kinds of valleys with different rocks and sediments. Valleys in this region consist of several types of streams which are clean, due to their filtration at the valley beds. Water resources, such as streams, springs, and rivers are used for drinking, irrigation, and other general-purpose usages. Due to years of regional conflict, the general water infrastructure needs to be upgraded, however since people need water for their day-to-day activities, it is necessary to characterize various sources of water to ensure their safety. Thus, this study aims to estimate the petrographic characteristics of the Paghman valleys and predict the resource suitability of the region through certain analyses: petrographic, gravel, and sieving analysis. The study is important since no such studies exist on this subject for this region, because of decades of war and much work remains to be done due to an ever-increasing population accompanied by air pollution which may affect the water resources of the region and thus causing health problems for people. The results provided through this investigation provide some preliminary quantification of heavy and light minerals, mechanical analysis, pH determination, electrical conductivity, and Cation and Anion concentrations of heavy and light minerals in water. Furthermore, as the regional population is steadily increasing, the authors highlight policy recommendations for a range of mitigation measures for the relevant authorities to keep water and soil quality within a safe range.

Amplitude Variation with Offset (AVO) Inversion for Reservoir Visualization: A Case Study of Taje Field, Niger Delta, Nigeria

Ebiegberi Oborie — 2024-02-29

Amplitude Variation with Offset (AVO) inversion analysis was performed on pre-stack seismic data and well information gathered from the shallow offshore area of the Niger Delta. This analysis aimed to improve reservoir visualization and employed the Hampson Russell Geoview, AVO, and STRATA software tools. The seismic data were provided in Seg-Y format, covering an in-line range from 4503 to 5569, an x line range from 1434 to 2026, and an angle of incidence range of 0 to 45°. The study centered on the Taje well_026. Within the subsurface, the authors identified five distinct reservoirs, labeled A to E, located at various depths ranging from 3057.50 to 3115.00 m, 3115.00 to 3157.50 m, 3157.50 to 3190.00 m, 3190.00 to 3200.00 m, and 3200.00 to 3239.00 m, respectively. These reservoirs exhibited different fluid compositions. Reservoir A, primarily composed of sandstone, contained brine, whereas Reservoirs B and D, dominated by shale, contained gas. On the other hand, Reservoirs C and E, both comprised of sandstone, held oil. Reservoir C is distinguished by its clean sandstone unit. The inversion results revealed that both Reservoirs C and E consisted of low impedance sand layers surrounded by higher impedance shale layers. The gas migrated from the reservoir and was trapped within the shale units due to deformation of the lithological units, likely induced by stress accumulation. This migration process was facilitated by the shale’s inability to undergo smearing, possibly as a result of faulting mechanisms.