Rapid urban expansion along Egypt’s northwestern Mediterranean coast requires reliable subsurface characterization capable of supporting both geotechnical safety and sustainable groundwater management. This study integrates 87 Electrical Resistivity Tomography (ERT) profiles with borehole logging data, including gamma ray (GR), spontaneous potential (SP), and granulometric analyses, to establish a high-resolution geotechnical and hydro-stratigraphic framework for the Ras El-Hekma coastal zone in Egypt. The integrated dataset resolved four principal subsurface units with distinct resistivity signatures, lithological compositions, and engineering characteristics, calibrated through co-located borehole logs and laboratory granulometric analyses. Statistical analyses revealed strong inverse relationships between resistivity and both porosity (r ≈ − 0.52; r ≈ − 0.85 for thickness-corrected values) and clay content (r ≈ − 0.78; 95% CI (− 0.85, − 0.69)), while GR values showed a strong positive correlation with clay percentage (r ≈ 0.95; p < 0.001). The third geoelectrical layer, dominated by clay-rich Pliocene shale, represents the most problematic geotechnical unit, characterized by resistivity values below 12 Ω·m, clay content exceeding 34%, and thicknesses ranging from approximately 1.5 to 3.5 m. Spatial analysis demonstrates marked NE–SW heterogeneity associated with buried oolitic ridges, sabkha environments, and localized saline intrusion. Based on integrated petrophysical signatures, the study area was classified into four competency zones (A–D), each linked to specific foundation and ground-improvement recommendations. The proposed workflow provides a transferable, cost-effective framework for coastal arid regions by combining geophysical imaging, borehole calibration, and statistical interpretation to support sustainable urban planning, infrastructure development, and subsurface risk assessment.
Raghda M. Abd Elhamid, A. Basheer, M.S. Toni et al.· Scientific Reports· 0 citations
This study integrates seismic interpretation, sequence‐stratigraphic analysis and petrophysical evaluation to characterise the Cenomanian hydrocarbon potential within the Bahariya Formation and Abu Roash ‘G’ Member at Horus Field, Alamein Basin. Seismic interpretation revealed ENE–WSW and ESE–WNW trending extensional normal faults, forming structural highs (horsts, tilted blocks) that act as primary hydrocarbon traps. The Abu Roash Formation exhibited the highest seismic reflector continuity, aiding robust structural mapping, while the underlying Bahariya, Kharita and Alam El Bueib formations showed increasing discontinuity downwards. Instantaneous Amplitude and Energy attributes were applied to quantitatively show deeper‐layers amplitude decay, reflector continuity and reveal subtle stratigraphic geometries obscured in conventional seismic data. Sequence stratigraphic analysis delineated two depositional sequences. BAHR‐SQ‐1 (Bahariya Fm), a siliciclastic‐dominated sequence (535–640 ft), comprises Lowstand (LST‐1: fluvial‐deltaic to shallow marine sandstones), Transgressive (TST‐1: mixed siliciclastics/carbonates) and Highstand (HST‐1: progradational sandstones) Systems Tracts. ARG‐SQ‐2 (Abu Roash ‘G’ Member; 525–675 ft), a carbonate/siliciclastic sequence, comprises a Transgressive Systems Tract (TST‐2: deep‐shelf dolomites) and a Highstand Systems Tract (HST‐2: progradational mixed facies). Petrophysical assessment identified both sequences as hydrocarbon‐bearing reservoirs but with distinct characteristics. The Upper Bahariya (HST‐1) offers volumetric potential (thickness 220–233 ft., porosity 29%–35%) but exhibits variable, generally poorer quality (lower net‐to‐gross: 2%–12%, higher shale volume: 15%–25%, higher water saturation: 32%–33%, limited pay: 4–29 ft). In contrast, the Abu Roash ‘G’ Dolomite (primarily TST‐2) demonstrates superior and consistent reservoir quality across wells (thickness 60–81 ft., net‐to‐gross: 15%–32%, lower shale volume: 5%–9%, porosity 21%–24%, lower water saturation: 28%–41%, hydrocarbon saturation 59%–73%, pay 12–23 ft). The cleaner lithology and favourable petrophysics make the Abu Roash ‘G’ the key contributor to hydrocarbon potential, despite its lesser thickness compared to the Bahariya. These results underscore the critical control of sequence stratigraphic architecture and depositional facies on reservoir distribution and quality, providing essential insights for future exploration targeting in analogous settings.
A. Shehata, A. Ismail, Mohamed I. Abdel‐Fattah et al.· Geological Journal· 0 citations
