A. Ogbamikhumi

This project presents an integrated 3D seismic interpretation and identification of hydrocarbon prospects of Yeager Field, which is located within the prolific Niger Delta Basin of Nigeria. There search has been performed using high-resolution 3D seismic data, integrated with well-login formation provided by the Shell Petroleum Development Company (SPDC) to identify subsurface structural and stratigraphic features that are relevant to hydrocarbon accumulation. A comprehensive fault mapping, horizon interpretation, seismic-to-well tie, velocity modeling, and depth conversion were undertaken and complemented by seismic attribute analysis comprising RMS amplitude, maximum amplitude, average energy, and average magnitude attributes. Thirty five (35) faults were identified dominated by growth faults, rollover anticlines, and synthetic-antithetic fault systems typical of the extensional regime of the Niger Delta. Several structural closures with trapping potential were identified from the time and depth structure maps, while seismic attributes indicated amplitude anomalies that suggested the presence of hydrocarbon in the reservoir sands of the Agbada Formation. The seismic-to-well tie provided a reliable time-depth relationship that increased the accuracy of horizon correlation by more than forty percent. The results indicate that fault-assisted closures, especially the rollover anticlines resulting from the growth faults, are the primary trapping mechanism in the field. Potential hydrocarbon prospects have been delineated using this integrated approach, providing a robust geological framework for future exploration and development planning in the study area. The importance of advanced 3D seismic interpretation in reducing exploration risk and optimizing hydrocarbon recovery in the complex structural setting of the Niger Delta Basin cannot be overemphasized.

This project work is focused on the volumetric estimation of Agbeju Field, Niger Delta using 3Dseismic data and well logs. Data used for this project include 3-D seismic data in SEG-Y format and suites of five well logs (Agbeju 01, Agbeju 02, Agbeju 03, Agbeju 04 and Agbeju X01). 9 major faults and 24 minor faults were delineated on the seismic data. The lateral extent of 3 hydrocarbon bearing reservoirs were delineated and mapped as blocks (Sand A, Sand B and Sand C) and evaluated showing the petrophysical values across the reservoirs having average porosity of 0.32, average pay thickness of 98.46ft, average net-to-gross ratio of 0.84, and average water saturation of 0.625. From prospect identification, the area of the drilled prospects within the reservoirs ranges from 452.8634 acres – 1196.512 acres. The estimated volumes of hydrocarbons within the drilled prospects is given by Gas initially in place for Sand A (554MMSCF), Sand B (163MMSCF) and Sand C (258MMSCF) and Oil initially in place for Sand B (22.4MMBBL) and Sand C (83.93SMMBBL). The result of the characterization of these reservoirs shows good productive sands with fair to good hydrocarbon saturation of 0.375, with sufficient hydrocarbon volumes necessary for field development and production.

This study attempts to access the quality, spatial variation and economic viability of A and C reservoirs across eight wells in the Alero Field. Suites of wireline well log data for the wells of the Alero Field were evaluated to characterize the reservoirs. From the quantitative and qualitative analyses carried out, it was revealed that reservoir A has the following petrophysical characteristics across the wells; Gross thickness 14.85m to 193.01m, shale volume 16% to 28%; total porosity: 31%to34%; effective porosity: 25% to 29%; permeability: 9962.25mD to 12912.90mD;
water saturation: 7% to 24%, while for reservoir C across the wells; shale volume10% to 36%%; total porosity: 28% to 33%; effective porosity: 21%to 29%; permeability: 10174.20mD to 12498.70mD; water saturation: 5%to 59%. The results show both reservoirs to exhibit favourable properties across the wells, including moderate to high net-to-gross (NTG) ratios, effective porosity, high hydrocarbon saturation, and good permeability. However, variations in shale content (VSh), water saturation, as well as pay zone thickness across the wells suggest
spatial heterogeneity in reservoir quality. Overall, reservoir A is found to be a more promising candidate for oil production, showing better permeability (10174.20mD to 12498.70mD) and overall hydrocarbon saturation (75% to 93%).

This study examined the sedimentological and geochemical characteristics of problematic soils within the Lagos segment of the Dahomey Basin, Southwestern Nigeria, to understand their composition, depositional setting, and engineering implications. Eight borehole samples (BH1–BH8) were analyzed for particle size distribution, water content, density, and plasticity characteristics, while representative samples (L2 and L5) underwent X-ray diffraction (XRD) analysis. The particle size distribution results showed that the soils are predominantly fine- grained comprising of clayey or silty materials to fine grained sand with mean grain sizes between 3.30ϕ and 6.83ϕ. Sorting values between 3.54 and 4.86ϕ classified them as very poorly sorted sediments deposited under fluctuating, low-energy coastal conditions. Water content ranged from 23.8 % to 36.9 %, density from 1.77 to 1.88 g/cm³, and void ratios from
0.65 to 0.81, indicating moist, moderately compacted soils with high porosity. The liquid limit and plasticity index values, ranging from 37.7–58.2 % and 21.3–32.6 % respectively, revealed high plasticity and significant swelling potential. XRD results confirmed montmorillonite (41–42 %) as the dominant mineral, alongside quartz (33–39 %) and minor actinolite or albite. These properties collectively explain the soils’ poor strength, high compressibility, and moisture sensitivity. The study concludes that the Lagos coastal soils are expansive and structurally unstable, requiring stabilization, effective drainage, or deep foundations to support safe and durable engineering development within the Dahomey Basin