Integrated Analysis of Sequence Stratigraphy, Seismic Interpretation and Petrophysical Data for Cenomanian Reservoirs (Horus Field, Alamein Basin, Egypt): Implications for Siliciclastic/Carbonate Reservoir Distribution and Quality

INTEGRATED STRATIGRAPHIC AND PETROPHYSICAL ASSESSMENT OF THE MADUKY FIELD, NIGER DELTA, NIGERIA: IMPLICATIONS FOR RESERVOIR ARCHITECTURE AND HYDROCARBON PROSPECTIVITY

The Maduky Field, situated within the Coastal Swamp depobelt of the Niger Delta Basin, represents a structurally complex and geologically heterogeneous marginal field with untapped hydrocarbon potential. This study integrates 3D seismic interpretation, well log correlation, sequence stratigraphy, and petrophysical analysis to characterize its reservoir architecture and evaluate hydrocarbon volumes. Structural mapping reveals prominent listric growth faults and rollover anticlines that define three main field compartments, each with distinct depositional and trapping characteristics. Sequence stratigraphic analysis, guided by five regionally correlated Maximum Flooding Surfaces (MFSs), delineates Genetic Sequences and system tracts (HST, TST, LST), each with unique parasequence stacking patterns and reservoir geometries. The highstand and lowstand system tracts host the most prolific reservoirs, characterized by clean, coarsening-upward sand bodies with high net-to-gross ratios and favorable porosity-permeability relationships. Petrophysical evaluation across five wells indicates effective porosity values of 20–34%, permeability ranging from 2.50 to 18 mD, and low water saturation (8–35%), confirming reservoir quality suitable for commercial exploitation. Crossplots further demonstrate the controls of porosity and depositional environment on fluid distribution and reservoir performance. The study identifies key hydrocarbon-bearing units sealed by marine shales associated with MFSs and quantifies Stock Tank Oil Initially In Place (STOIIP) across fault blocks, highlighting potential development zones. These insights support the redevelopment of Maduky Field and provide a scalable model for optimizing marginal field performance in mature deltaic basins.

3D Seismic Interpretation and Geological Modelling for Petroleum Reserves Estimation of I Sequence, Lower Miocene, X Field, Block Y, Malay – Tho Chu Basin, Viet Nam

Seismic attributes are widely used to enhance geological interpretation by extracting quantitative information from seismic data. They provide insights into both structural and stratigraphic features, enabling interpreters to detect subtle changes in lithology, continuity, and geometry of subsurface formations. Attributes are especially useful in improving the resolution of seismic images, helping to delineate horizons, identify fault patterns, and visualize depositional features. This study focuses on using seismic attribute analysis to clarify the distribution of sand bodies within a reservoir interval. The objective is to identify zones with favourable sand development, define their geometry and connectivity, and outline areas with high hydrocarbon reservoir potential. The interpreted I Sequence was divided into three sub-sequences, each modelled with a geological grid size of 50m×50 m and subdivided into 150 layers. The porosity model showed mean values ranging from 0.228 to 0.2484 across the main reservoir zones, while water saturation varied from 0.90659 to 0.92747. After calculating seismic attributes, the authors delineated sand bodies in the I38_upper layer located in the North–Northwest, Northeast, and smaller bodies in the South. In the I90 layer, sand bodies were identified in the North–Northeast, East, and Southeast, along with narrow, laterally restricted sands in the western part of the study area. The P2 reserve with 50% confidence for the most potential interval (I23–I38) was estimated at 86 million cubic meters after running 200 cases.

Stratigraphic Trap Configurations, Seismic Sequence and Facies Analyses of the ‘Ekwai’ Field: Implications for Hydrocarbon Exploration In The Niger Delta

Stratigraphic traps have become increasingly important exploration targets in the mature Niger Delta Basin because of the progressive depletion of conventional structural traps. This study utilized threedimensional (3-D) seismic data, wireline logs, checkshot surveys, and well deviation data from three wells (KC1, KC2, and KC3) to characterize the stratigraphic trapping configuration, sequence stratigraphy, and seismic facies of the Ekwai Field in the eastern Niger Delta. The adopted workflow involved well-to-seismic correlation, structuralinterpretation, sequence stratigraphic analysis, seismic facies classification, and depositional environment interpretation. The results revealed stratigraphic traps associated with lateral facies changes, depositional pinchouts, and five distinct channel-fill architectures (Types I–V). Among these, Channel Types II, III, and IV exhibit favourable seismic attributes, coarse-grained depositional characteristics, and high hydrocarbon prospectivity, whereas Types I and V are understood to be shale-dominated and less prospective. Sequence stratigraphic analysis established five sequence boundaries (SB1– SB5) and four maximum flooding surfaces (MFS1–MFS4), which were correlated across Wells KC1, KC2, and KC3 to define the depositional sequences and associated systems tracts. Seismic facies analysis identified distinct facies assemblages based on reflection configuration, continuity, amplitude, and frequency, enabling the interpretation of lithological variations, depositional energy, and sedimentary environments throughout the field. The integrated interpretation demonstrates that hydrocarbon accumulation within the Ekwai Field is controlled by the interaction of depositional architecture, sequence stratigraphy, and stratigraphic trapping mechanisms. The developed geological model enhances reservoir characterization, reduces exploration uncertainty, and provides a robust framework for hydrocarbon prospect evaluation and future field development within the eastern Niger Delta. The 3-D seismic data conducted in the Ekwai field of the eastern Niger Delta focused on understanding the stratigraphic framework. The main objectives were to identify trapping configurations of stratigraphic traps, and pinpoint channels with potential for hydrocarbon accumulation and analyse facies. The research utilized wireline logs, checkshot, and well deviation data from three wells. The methods included stratigraphic, seismic sequence and seismic facies analyses. Stratigraphic analysis uncovered traps resulting from facies changes, stratigraphic pinch-outs, and five channel fills categorized as types I, II, III, IV, and V. among these, channel types II, III, and IV exhibited promising hydrocarbon potential. In Sequence stratigraphy, four stratigraphic sequence boundaries (SBI, SB2, SB3, SB4 and SB5) and four intrasequence Maximum Flooding Surfaces (MFS1, MFS2, MFS3, and MFS4) were identified. SB1 and SB2 were correlated across KC1, KC2 and KC3 Wells. Facies analysis help to distinctively differentiate various facies units and internal reflective configurations, revealing the deposition environment. 

Sequence stratigraphic controls on reservoir quality: Insights from the Middle Miocene Birsa Formation, Gulf of Hammamet, Southern Mediterranean

Sequence Stratigraphic Evolution of Late Miocene–Early Pliocene in the Central Song Hong Basin, Vietnam: Controls on Sediment Routing and Reservoir Predictability

The Cenozoic Song Hong Basin (SHB), in the northwestern East Vietnam Sea (South China Sea), underwent major stratigraphic and depositional changes during the Late Miocene–Early Pliocene, a critical interval shaped by relative sea‐level fluctuations, tectonics, and intensified monsoonal sediment supply. These factors reconfigured sediment dispersal and paleotopography, controlling the distribution of reservoir and seal architectures. Understanding these controls is essential for reconstructing depositional histories and assessing hydrocarbon potential. This study provides the first high‐resolution characterization of the Late Miocene–Early Pliocene succession in the western sector of the central SHB by integrating seismic interpretation, biostratigraphy, gamma‐ray log analysis, and forward stratigraphic modeling. Three third‐order sequences, constrained by biostratigraphy (SU1: 6.8–5.3 Ma, falling‐stage systems tract [FSST]; SU2: 5.3–3.8 Ma, LST; and SU3: 3.8–2.3 Ma, TST), record the evolution from falling‐stage shelf‐margin delta deposition to lowstand basin‐floor sedimentation and subsequent transgressive marine flooding, reflecting changes in accommodation, sediment supply, and climatic conditions from the humid Late Miocene to the cooler, drier Early Pliocene. Sand‐rich shelf‐margin deltas and basin‐floor turbidite fans developed during SU1 and SU2, sourced mainly from the Vietnamese hinterland, constitute the principal reservoir targets, whereas the mud‐rich transgressive deposits of SU3 provide an effective regional seal. Sensitivity analyses using forward stratigraphic modeling indicate that sediment discharge, sand–mud ratio, and paleotopography exert first‐order controls on turbidite fan geometry, sand dispersal, and reservoir connectivity. Comparison between the modeled depositional trends and 3D s eismic root mean square (RMS) amplitude anomalies demonstrates the complementary value of integrating process‐based forward modeling with seismic interpretation for predicting sand‐prone depositional systems. These results provide new insights into the controls on Late Miocene–Early Pliocene basin evolution and establish a predictive framework for reservoir distribution in monsoon‐influenced continental margin basins.

Hydrogeological Response to Low-Magnitude Seismicity: Fracture Sealing, Ground Deformation, and Lake Depletion in the Sikkim Himalaya

Earthquake-induced fracturing and microcrack development in subsurface strata are widely recognized as important processes influencing seepage and the hydrological behaviour of surface water bodies, particularly in tectonically active mountainous terrains. However, the hydrogeological response to repeated low-magnitude (<4) seismic events remains poorly understood. This study presents an integrated geoelectrical and remote sensing investigation of the Nagi Lake region in the Sikkim Himalaya, India, based on Vertical Electrical Sounding (VES) surveys conducted in May 2022 and March 2026, following a seismic sequence of 74 low-magnitude earthquakes recorded during February 2026. Comparative analysis of four VES profiles (VES1–VES4), supported by validatory factor analysis, reveals spatially heterogeneous changes in subsurface electrical characteristics between the two survey periods. VES1, VES2, and VES3 indicate reduced signatures of pre-existing microcracks that are consistent with sediment densification and partial sealing, whereas VES4 suggests localized development or persistence of microfractures. Because the surveys span approximately four years, these changes likely reflect the combined influence of long-term hydrogeological, environmental, and geomorphic processes, with the February 2026 seismic sequence representing one potential contributing factor rather than the sole driver. To further evaluate ground deformation, Sentinel-1A Synthetic Aperture Radar (SAR) data acquired between January 2019 and March 2026 were analysed using Persistent Scatterer Interferometric SAR (PS-InSAR). The results indicate cumulative Line-of-Sight (LOS) displacements ranging from −17.9 cm (movement away from the satellite) to +3.5 cm (movement toward the satellite) in the vicinity of Nagi Lake, reflecting localized surface deformation with millimetre-scale precision. These observations provide complementary evidence of ongoing subsurface adjustment that may promote sediment compaction and microcrack modification. Overall, the study demonstrates measurable temporal changes in the subsurface structure of the Nagi Lake area and suggests that repeated low-magnitude seismicity may contribute to subsurface restructuring alongside other environmental processes. The findings highlight the value of integrating geophysical monitoring and satellite-based deformation analysis for understanding groundwater–surface water interactions and supporting the sustainable management of vulnerable Himalayan water bodies.