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In order to interpret the airborne magnetic data and to evaluate the approximate location, depth, and geometry of the magnetic sources within Obudu area using standard Euler deconvolution method, high resolution aeromagnetic data over the area was processed digitally and analyzed using Oasis Montaj 8.5 software. Data analysis and enhancement techniques including reduction to equator, horizontal derivative, first and second vertical derivatives, upward continuation and regional-residual separation were carried out. Standard Euler deconvolution for structural indices of 0, 1, 2, and 3 were obtained. Results show that the total magnetic intensity ranges from -122.9nT to 147.0nT, regional intensity varies between -106.9nT to 137.0nT, while residual intensity ranges between -51.5nT to 44.9nT indicating the masking effect of deep-seated structures over surface and shallow subsurface materials. Results also show that the positive residual anomalies have a NE-SW orientation which coincides with the trend of major geologic structures in the area. Euler deconvolution for all the structural indices has depth to magnetic sources ranging from <0m to >2000m. Interpretation of the various structural indices revealed the locations and depths of the source bodies and the existence of geologic models including sills, dykes, pipes, and spherical structures. This area is characterized by shallow basement materials and represents a good prospect for solid mineral exploration. [ABSTRACT FROM AUTHOR]

The geomechanical characterization of the reservoirs of "Beta Field" was carried out to predict the stability of hydrocarbon reservoir rocks and hence, mitigate drilling and exploitation challenges within offshore Niger Delta. Gamma ray, sonic, and density logs from four wells within the field, including core data and 3D reflection seismic volume from the area, were integrated to determine rock mechanical and petrophysical properties from empirical equations, and generate 3D geomechanical models using Petrel and Ms-Excel software. Principal stresses operating within the reservoirs and pore pressure were also estimated from empirical models. Cross plots of these rock parameters were obtained to ascertain the relationship between them and obtain model equations. Results show that the rock mechanical properties have lower values in sand units than shale units with petrophysical parameters having lower values in shale. Average values of 13.70GPa, 0.33, 13.30GPa, 32.32GPa, 5.12GPa, 0.07, and 0.022mD were obtained in shale; while 0.30, 10.94GPa, 0.30, 12.76GPa, 25.19GPa, 4.11GPa, 0.19, and 192.00mD were recorded in sand for Young's modulus, Poisson ratio, bulk modulus, uniaxial compressive strength, shear modulus, effective porosity, and permeability respectively. Mean pore pressures observed in sand and shale units are 13,683psi and 15,662psi while mean total vertical stress, maximum and minimum horizontal stresses recorded in the reservoirs are 28,392psi, 25,537psi and 20,781psi respectively. Comparative analysis of obtained rock mechanical and strength parameters with the principal stresses operating within the reservoirs show that the studied reservoirs and by extension reservoirs of this petroleum play are stable. [ABSTRACT FROM AUTHOR]

Spectral analysis of high-resolution airborne magnetic data of part of Benue Trough was used to estimate the depths of anomalous magnetic sources within the study area. This paper was aimed at the determination of sedimentary thickness of the study area and to infer favourable areas for possible petroleum exploration. Several data enhancement techniques were used to digitally enhance the data to improve the signal-to-noise ratio. The total magnetic intensity was subjected to regional - residual separation using polynomial fitting of the first order, with the residual field revealing magnetic intensity values ranging from -79.8 to -16.5nT. Several clusters of circular magnetic anomaly closures with very clear amplitudes which occur especially in the northern and mid part of the area revealed edges of intrusive bodies. The structures observed within the location from the residual maps revealed dominant trends in the NE-SW and N-S direction. The result of 2D spectral analysis revealed a two-depth model, with the depth to the first layer (D1) varying from 0.135 km to 0.200 km with an average depth of 0.158 km while second layer depth (D2) varies from 2.585 km to 4.878 km with the average depth of 3.415 km. This result therefore, indicates that the average basement depth of the study area as deduced from power spectrum inversion is about 3.415km. The mean sedimentary thickness of 3.415km obtained and the near absence of intrusive bodies especially in the northern part of the study area thus reveal favourable conditions for hydrocarbon exploration. [ABSTRACT FROM AUTHOR]